Biomedical subjects

P Troncoso

Publications and source records attributed to P Troncoso.

At least 19 recordsLinked to original sources

PubMed2001

Genome-wide allelotyping analysis reveals multiple sites of allelic loss in gallbladder carcinoma.

Although gallbladder carcinoma (GBC) is a highly malignant neoplasm, there is very limited information about the molecular changes involved in its pathogenesis. To identify the chromosomal locations of putative tumor suppressor gene loci involved in the pathogenesis of GBC, we conducted a genome-wide allelotyping or loss of heterozygosity (LOH) analysis of GBCS: Microdissected tissue from 24 archival GBCs and their matched control DNAs were analyzed for PCR-based LOH using 169 microsatellite markers spanning all nonacrocentric autosomal arms and the X chromosome. The chromosomal arms with the greatest frequencies of LOH (> or = 60%) were 3p, 6q, 7q, 8p, 9p, 9q, 11q, 12q, 17p, 18q, 19p, 22q, and XQ: The average fractional allele loss index in GBC cases was high (0.43) and frequent breakpoints were detected in gallbladder tumors. Of interest, 21 different regions of frequent LOH (hot spots) defined as > or = 50% for individual GBC samples were detected in this neoplasm, nearly half of them confined to one microsatellite marker. We conclude that in GBC at least 21 chromosomal regions with frequent allele losses are involved, suggesting that several putative tumor suppressor genes are inactivated in its pathogenesis. Overall, these data provide global estimates of the extent of genetic changes leading to GBC and will be useful for the identification of new tumor suppressor genes and for multiple new markers for translational research.

Adenocarcinoma↗

PubMed2001

Limiting the location of putative human prostate cancer tumor suppressor genes on chromosome 18q.

We studied loss of heterozygosity (LOH) on the long arm of human chromosome 18 in prostate cancer to determine the location of a putative tumor suppressor gene (TSG) and to correlate these losses with the pathological grade and stage of the cancer. Of 48 specimens analysed 17 (35.4%) lost at least one allele on chromosome 18q. All the specimens with allelic losses lost at least one allele within chromosomal region 18q21. Allelic losses picked at D18S51 (19%) and D18S858 (17%). A 0.58 cM DNA segment that includes the D18S858 locus and is flanked by the microsatellite loci D18S41 and D18S381, was lost in eight (47%) of 17 specimens with allelic losses. This segment was designated as a LOH cluster region 1 (LCR 1). Although Smad2 resides within LCR 1, it was not mutated in any of the six prostate cell lines (five prostate cancer cell lines and one immortalized prostate epithelial cell line) analysed, suggesting that it is not a candidate TSG in prostate cancer. A second LCR at 18q21, LCR 2, includes the D18S51 locus and is flanked by the D18S1109 and D18S68 loci, which are separated by 7.64 cM. LCR 2 was lost in six (35%) of the 17 specimens with chromosome 18q losses. These results suggest that chromosome 18q21 may harbor two candidate prostate cancer TSGs. The candidate TSGs DCC and Smad4 are located centromeric to the LCRs. No alleles were lost within or in close proximity to these genes, suggesting that they are not targets for inactivation by allelic losses in prostate cancer. Although there was no obvious correlation between chromosome 18q LOH and the pathological grade or stage, three (37.5%) of eight low-grade cancers and nine (32.1%) of 28 organ-confined cancers lost alleles at 18q21, suggesting that allelic losses are relatively early events in the development of invasive prostate cancer.

Chromosome Mapping↗

PubMed2001

Analysis of clinicopathologic factors predicting outcome after radical prostatectomy.

BACKGROUND: A variable biochemical failure rate has been reported for patients undergoing radical prostatectomy. The authors analyzed their 1987-1993 prostatectomy experience retrospectively to stratify the risk of failure in order to appropriately select patients who potentially may benefit from adjuvant therapy. METHODS: A stepwise logistic regression was used to identify variables associated with biochemical failure in 265 patients who underwent radical prostatectomy only. Prostate tumors were examined by one pathologist using 4-mm step sections. Numerous clinicopathologic variables were evaluated, and the neoplasms were subclassified into five pathologic categories based on tumor extent and margin status. Actuarial projections of biochemical failure were created using the Kaplan-Meier method. RESULTS: Pathologically, 56.2% of the tumors were organ-confined with negative margins, 12.8% had a positive surgical margin without evidence of extraprostatic extension (EPE), 24.2% had EPE (17% with negative margins and 7.2% with positive margins), and 6.8% had seminal vesicle involvement. The Gleason score was > or = 7 in 86.4% of the total population. Values for the preoperative prostate specific antigen assay were < or = 4.0 ng/mL in 23.4% of the men and > 10 ng/mL in 27.7%. The overall observed biochemical failure rate in this patient group with a minimum 48 months of follow-up was 15.5%. Overall, stepwise logistic regression analysis revealed that pathologic category was the variable most strongly associated with biochemical failure and that vascular invasion was the only other examined variable associated with failure. CONCLUSIONS: The combination of pathologic category and the prostatectomy Gleason score can stratify a patient's probability of biochemical failure into three distinct groups and can identify the appropriate patients who may benefit from novel adjuvant therapeutic strategies.

Adult↗

PubMed2001

Leptin and prostate cancer.

BACKGROUND: Higher prostate cancer mortality rates among US immigrants from countries with lower rates suggest environmental influences on prostate carcinogenesis (e.g., diet, body composition). METHODS: In a study identifying determinants of clinically relevant prostate cancer, we compared plasma concentrations of leptin, an adiposity-related hormone, in 48 men with tumors </= 0.5 cc measured after radical prostatectomy and 151 men with tumors > 0.5 cc in volume or with histologic evidence of extraprostatic extension but without metastases ("high-volume disease"), matched by age (+/- 5 years) and year at diagnosis (+/- 1 year). RESULTS: Men with high-volume disease exhibited higher leptin concentrations overall and after stratification by age, testosterone level, height, and body mass index (BMI). Analysis revealed that men with elevated leptin concentrations had an increased risk of diagnosis with high-volume disease (odds ratio (OR) = 2.35, 95% confidence interval (CI) = 1.01-5.44), as did men with high leptin and high testosterone (OR = 9.73, 95% CI = 2.05-46.24) and men >/=5'8" with high leptin (OR = 3.67, 95% CI = 1.40-9.63). CONCLUSIONS: Leptin may affect the risk of clinically relevant prostate cancer through testosterone and factors related to stature and obesity.

Aged↗

PubMed2001

Antitumor efficacy of 26-fluoroepothilone B against human prostate cancer xenografts.

BACKGROUND: Epothilone compounds (e.g. epothilones A and B) represent a new structural class of microtubule inhibitors with the remarkable ability to inhibit tumor growth of multidrug-resistant cell lines at low nanomolar or even subnanomolar concentrations. Unfortunately, this therapeutic efficacy has only been achieved to date with a narrow therapeutic window. Hence, other structural analogs of compounds such as epothilone B are currently being synthesized in the hope that they will demonstrate equivalent antitumor efficacy with reduced systemic toxicity. PURPOSE: To evaluate the relative efficacy and toxicity of selectively modified epothilone compounds. METHODS: Compounds were initially screened for relative cytotoxicity against the human prostate cancer cell lines PC3, LNCaP, MDA PCa 2a and MDA PCa 2b. Growth inhibitory IC50 values of 0.5 to 4 nM were obtained. From this initial screen, one epothilone compound, 26-fluoroepothilone B, was chosen for further evaluation against the growth of s.c.-implanted MDA PCa 2b- and PC3-derived prostate tumors in athymic nude mice. The compound was administered intravenously at 2, 5 and 10 mg/kg after the tumors had reached 300 mm3. Two control groups were used: paclitaxel (40 mg/kg) and saline. RESULTS: Following treatment with 10 mg 26-fluoroepothilone B/kg, there was a sustained decrease in tumor size for 30 days reaching a maximal reduction of 80% when compared with tumor growth in the saline control group. Sustained suppression (> 20 days) of tumor growth was observed following the second drug injection. Although a maximal body weight loss of 30% occurred after the second injection, all mice completely regained their initial body weight in 20 days. A lower dose (2 mg/kg) produced a 58% maximal reduction in tumor size and a 20% body weight loss. Minimal inhibition of tumor growth, however, was obtained with paclitaxel at a maximally tolerated dose (40 mg/kg). Other epothilones tested were either less effective and/or more toxic than 26-fluoroepothilone B. This new fluorinated epothilone compound supports the growth of paclitaxel-dependent Tax-18 mutant CHO cells and produces microtubule bundles similar to those produced by paclitaxel, indicating that the two drugs share a similar mechanism of action. CONCLUSION: A new fluorinated epothilone compound, 26-fluoroepothilone B, has been described that stabilizes microtubule structures based on its support of growth of a mutant paclitaxel-dependent CHO cell line. Its antitumor activity against human prostate cancer in nude mice is superior to that of paclitaxel at equivalent toxic doses. Further research is required to determine optimal dosing strategies and to fully assess the compound's activity against other malignant diseases.

Animals↗

PubMed2001

Interobserver reproducibility of Gleason grading of prostatic carcinoma: urologic pathologists.

Gleason grading is now the most widely used grading system for prostatic carcinoma in the United States. However, there are only a few studies of the interobserver reproducibility of this system, and no extensive study of interobserver reproducibility among a large number of experienced urologic pathologists exists. Forty-six needle biopsies containing prostatic carcinoma were assigned Gleason scores by 10 urologic pathologists. The overall weighted kappa coefficient kappa(w) for Gleason score for each of the urologic pathologists compared with each of the remaining urologic pathologists ranged from 0.56 to 0.70, all but one being at least 0.60 (substantial agreement). The overall kappa coefficient kappa for each pathologist compared with the others for Gleason score groups 2-4, 5-6, 7, and 8-10 ranged from 0.47 to 0.64 (moderate-substantial agreement), only one less than 0.50. At least 70% of the urologic pathologists agreed on the Gleason grade group (2-4, 5-6, 7, 8-10) in 38 ("consensus" cases) of the 46 cases. The 8 "nonconsensus" cases included low-grade tumors, tumors with small cribriform proliferations, and tumors whose histology was on the border between Gleason patterns. Interobserver reproducibility of Gleason grading among urologic pathologists is in an acceptable range.

Humans↗

PubMed2001

Activator protein 2alpha transcription factor expression is associated with luminal differentiation and is lost in prostate cancer.

PURPOSE: Prostate cancer progression is associated with deregulation of genes like E-cadherin, p21/WAF1, MMP-2, VEGF, and IGF-binding protein, 3 and 5, all of which are target genes for the transcription factor activator protein 2alpha (AP-2alpha). We, therefore, hypothesize that the development/progression of prostate cancer is associated with changes in the expression of AP-2alpha. EXPERIMENTAL DESIGN: We used immunofluorescent staining to assess the presence of AP-2alpha in normal, benign, and malignant human prostate tissues and to correlate its expression with tumor grade and stage. RESULTS: We found that although AP-2alpha was expressed in normal prostate epithelium, it was not expressed in 30 prostate cancer specimens of different Gleason scores. Moreover, AP-2alpha protein was present in the luminal cell layer but not in the basal cell layer of the normal epithelium, which indicated that the loss of AP-2alpha staining in the prostate cancer specimens was not attributable to a lack of AP-2alpha-expressing cells. Further analysis demonstrated the presence of AP-2alpha in 2 (40%) of 5 atrophic normal epithelium, in 4 (24%) of 17 cases of benign prostatic hyperplasia, and in 2 (13%) of 13 cases of high-grade prostatic intraepithelial neoplasia. Loss or reduction in AP-2alpha expression was also observed in LNCaP, LNCaP-LN3, and PC3M-LN4 cell lines. CONCLUSIONS: Our data demonstrate that AP-2alpha expression is associated with normal luminal differentiation and that a loss of AP-2alpha expression occurs early in the development of prostate adenocarcinoma. Loss of AP-2alpha may lead to deregulation in AP-2alpha target genes that normally regulate cellular growth and differentiation.

Biomarkers, Tumor↗

PubMed2000

Detailed mapping of prostate carcinoma foci: biopsy strategy implications.

BACKGROUND: Prostate carcinoma exhibits considerable anatomic heterogeneity. Detailed characterization of prostate carcinoma distribution could lead to improved detection procedures and biopsy strategies. We mapped all 607 tumor foci from 180 serially sectioned whole mount radical prostatectomy specimens and used a computer algorithm to plot and summarize the distribution of these foci. We investigated whether specimen and clinical variables predicted differences in tumor distribution. METHODS: The volume and anatomic location of each tumor focus were determined and digitized. A computer-based algorithm was used to fit the digitized tumor foci to a paradigm prostate. Pseudo-color summary plots of tumor distribution then were computed for selected cases. RESULTS: Of the 180 specimens, 149 (83%) specimens had more than one cancer focus. Most foci (448 of 607 tumor foci, 74%) were in the peripheral zone (PZ). PZ foci near the apex had a significant midline component. Toward the base, PZ foci diverged laterally. Only 3 (2%) of 180 specimens contained foci solely in the transition zone (TZ). Total TZ cancer volume was </= 0.5 cm(3) in 55% (52 of 94) of patients. Computer plots of patients with T1c classification (UICC/AJCC) and specimen Gleason score </= 6 had greater proportions of TZ tumor. CONCLUSIONS: Almost all TZ foci occurred with PZ foci. The small volume of most TZ foci may explain the ineffectiveness of TZ biopsies to detect additional cancers during screening. Further, our results suggested that biopsies may be more effective if laterally directed biopsy samples are obtained nearer to the base of the prostate and if apical biopsy samples are obtained more medially.

Algorithms↗

PubMed2000

Epidemiologic determinants of clinically relevant prostate cancer.

While tumor volume and Gleason scores are the best available prognostic indicators for prostate cancer, contemporary predictive methods are unable to identify which men with Gleason scores of 7 have clinically insignificant tumors that will not progress and which men will develop highly aggressive prostate cancer. Our objective was to evaluate potential environmental determinants of significant prostate cancer. Subjects were patients identified from a university-based hospital and tertiary cancer center who had undergone radical prostatectomy for prostate cancer. Cases were 103 patients whose tumor volumes were </=0.5 ml. The comparison group was comprised of 225 men with larger-volume disease or with histologic evidence of extracapsular extension but without lymph node involvement. The matching criteria were ethnicity, age at diagnosis (+/-5 years), and date of diagnosis (+/-1 year). Epidemiologic data, current weight, and height were obtained. The comparison group was significantly more likely than cases to be current smokers (7.6% vs. 3.9%) and to report more pack-years smoked (30.1 vs. 23.0 years, p = 0.06). Cases tended to weigh less (85.2 vs. 87.1 kg, p = 0.1) and have lower body mass indices (26.8 vs. 27.6, p = 0.07). A similar trend was evident for weight at age 40 (79 vs. 81 kg). Cases reported a mean weight gain of 4.9 kg compared with 6. 6 kg in the comparison subjects (p = 0.05) between the ages of 25 and 40. There was no significant difference in weight gain from age 40 to current age. Cases were more likely to report having prostate cancer screening (90% vs. 80%, p = 0.02). Cases with Gleason scores </=7 (3 + 4, with 3 being the dominant grade) were younger at diagnosis than those with scores of 7 (4 + 3, with 4 being the dominant grade), were more likely (93%) to have had prostate screening, were less likely to be current smokers (4%), reported the fewest pack-years smoked (21.5 vs. 28.6 years for high-score cases and 30.1 for comparison subjects), and had the lowest average weight gain from ages 25 to 40 (4.62 vs. 6.31 kg for high-score cases). Weight gain in early adulthood and smoking thus appear to be important predictors of virulent prostate cancer. Our data also suggest that prior screening is associated with diagnosis of lower-volume and lower-score disease.

Age Factors↗

PubMed2000

Neoadjuvant chemotherapy and hormonal therapy followed by radical prostatectomy: feasibility and preliminary results.

PURPOSE: We assessed the feasibility and efficacy of integrating chemotherapy and androgen ablation with radical prostatectomy in patients with locally advanced prostate cancer. The neoadjuvant approach was adopted because it allows an in situ assessment of antitumoral activity. PATIENTS AND METHODS: Thirty-three patients were enrolled who met the clinical criteria of stage T1-2, Gleason score of >/= 8 or T2b-T2c, Gleason score of 7 and prostate-specific antigen (PSA) level greater than 10 ng/mL (n = 15), or clinical stage T3 (n = 18). Therapy consisted of 12 weeks of ketoconazole and doxorubicin alternating with vinblastine, estramustine, and androgen ablation followed by prostatectomy. The ability of neoadjuvant chemotherapy and hormonal therapy to induce a 20% rate of pT0 in the prostatectomy specimen as well as surgical feasibility were assessed. RESULTS: Chemotherapy complications were comparable to those reported with this regimen previously. No major intraoperative complications occurred. Postoperative complications occurred in 10 (33%) of 30 patients. One patient died at home after discharge (postoperative day 17; no autopsy was performed). Ten (33%) of the 30 patients had organ-confined disease, and 20 (70%) of 30 had extraprostatic extension; 11 (37%) of the 30 had positive lymph nodes. Only five (17%) of 30 exhibited positive surgical margins. All patients achieved an undetectable PSA level postoperatively, and 20 of the surviving 29 patients remain without disease recurrence with a median follow-up of 13 months (range, 9 to 18 months). CONCLUSION: Chemotherapy and androgen ablation followed by radical prostatectomy was feasible in patients with locally advanced prostate cancer. Although the goal of achieving a 20% rate for pT0 status was not achieved, we believe this type of integrated therapeutic strategy should be investigated further for its ability to alter the course of regionally advanced prostate cancer.

Adult↗

PubMed2000

A comparative analysis of sextant and an extended 11-core multisite directed biopsy strategy.

PURPOSE: The 3 tumor locations unsampled by conventional sextant biopsies that have been identified on composite 3-dimensional reconstruction of 180 radical prostatectomy specimens are the anterior transition zone, midline peripheral zone and inferior portions of the anterior horn in the peripheral zone. We evaluated an 11-core multisite directed biopsy scheme incorporating these alternate areas and conventional sextant biopsies in 362 patients from 2 institutions. MATERIALS AND METHODS: Patients without a prior diagnosis of cancer underwent ultrasound guided 11-core biopsies which included conventional sextant and 3 alternate sites. All specimens were separated for specific location identification. Biopsy was performed in 183 patients at MD Anderson Cancer Center (group 1) and in 179 at Toronto General Hospital (group 2). All group 2 and 54% of group 1 patients (98 of 183) had a prior biopsy negative for cancer. RESULTS: Median prostate specific antigen was higher in group 2 than in group 1 patients (11.5 versus 9.5 ng./ml., p = 0.016). Overall a 33% increase (36 of 110 patients) in cancer detection was observed when biopsy technique included the alternate areas (p = 0.0021). The anterior horn was the most frequently positive biopsy site followed by the transition zone and midline sites. The 11-core technique had significantly better cancer detection rates when digital rectal examination and transrectal ultrasound were normal, and in men with serum prostate specific antigen between 4.1 and 10 ng./ml. CONCLUSIONS: Biopsies of the alternate sites suggested by our simulation studies are feasible and reproducible. This new strategy significantly enhanced (p = 0.0075) prostate cancer detection compared to conventional sextant biopsies in men undergoing a repeat procedure.

Adult↗

PubMed2000

Strategy for repeat biopsy in patients with high grade prostatic intraepithelial neoplasia.

PURPOSE: The finding of high grade prostatic intraepithelial neoplasia in a biopsy specimen without prostate cancer warrants repeat biopsy because of the risk of concurrent cancer. However, to our knowledge the optimal repeat biopsy technique has not yet been defined. We determined the optimal subsequent biopsy strategy for detecting concurrent cancer in patients diagnosed with high grade prostatic intraepithelial neoplasia. MATERIALS AND METHODS: Of 63 men with isolated high grade prostatic intraepithelial neoplasia on initial biopsy 45 underwent repeat biopsy within 1 year. Certain biopsy patterns were used for repeat biopsy, including only the neoplasia site in 8 men, sextant in 12, sextant plus bilateral transition zone in 13 and 11 core multisite directed (sextant, bilateral transition zone, bilateral anterior horn of the peripheral zone and midline peripheral zone) in 12. We compared the location of high grade disease on the initial biopsy with the cancer site on repeat biopsy. RESULTS: Repeat biopsy revealed cancer in 10 of the 45 men (22%), and the sites of high grade prostatic intraepithelial neoplasia and cancer correlated in 6. Cancer was detected at the sextant locations in 9 men. Of the 15 cores positive for cancer 8 were at the original high grade neoplasia site, 6 at a random sextant biopsy site and 1 in the transition zone. High grade disease was discovered bilaterally in 1 man, while prostatic intraepithelial neoplasia and cancer were detected on the same side in the remaining 9. CONCLUSIONS: The optimal repeat biopsy strategy for patients with high grade prostatic intraepithelial neoplasia has not yet been determined but at a minimum it should include targeting the area of known high grade disease and the ipsilateral sextants.

Biopsy↗

PubMed2000

TabBO: a model reflecting common molecular features of androgen-independent prostate cancer.

We established two human prostate cancer cell lines, MDA PCa 2a and MDA PCa 2b, the TabBO model system, that reflect common features of human androgen-independent prostate cancer that are not present in other model systems: bone origin, prostate-specific antigen production, androgen receptor expression, and androgen sensitivity. We therefore hypothesized that molecular pathways in our model system reflect common alterations responsible for the progression of a subset of human prostate cancer. Progression to androgen independence has been hypothesized to be largely associated with impairment of the regulation of cell growth or apoptosis of prostate cancer cells. Therefore, in this study, we examined molecular markers known or suspected to be important in prostate cancer progression and key regulators of cell growth and apoptosis: p53, p21WAF1/CIP1, Bcl-2, Bax, retinoblastoma (Rb), and p16INK4A/MITS1. We analyzed the expression of these markers in the cell lines, their tumor of origin, and tumors derived from the cell lines by s.c. inoculation into nude mice. DNA sequencing of the entire open reading frames of the p53 and p21 genes revealed no mutations. Additionally, accumulation of the p53 protein was not found by Western blot analysis, nor was overexpression of the Bcl-2 oncoprotein detected. Bax expression was detected in MDA PCa 2a cells, whereas it was absent in MDA PCa 2b. Rb and p16 protein expression was normal as measured by both Western blot and immunochemical analyses. Immunohistochemical studies of p53, p21, Bcl-2, and Rb in both samples from the original human cancer from which the lines were derived and mouse xenografts derived from the lines revealed similar levels of protein. These results are consistent with reports indicating that 40-50% of bone metastases of prostate cancer have wild-type p53, 50-70% do not overexpress the Bcl-2 protein, and mutations in the p21 gene are rare. Therefore, we conclude that MDA PCa 2a and MDA PCa 2b reflect molecular pathways in a common subset of human androgen-independent prostate cancer and that important molecular players in apoptosis (namely, p53 and Bcl-2) seem to be intact in this subset of androgen-independent prostate cancer. Understanding the signal-transduction pathways operating in these cell lines may help to identify therapeutic targets for prostate cancer.

Androgens↗

PubMed2000

Relative expression of type IV collagenase, E-cadherin, and vascular endothelial growth factor/vascular permeability factor in prostatectomy specimens distinguishes organ-confined from pathologically advanced prostate cancers.

The tumor grade (Gleason score) in the biopsy and pretherapy prostate-specific antigen level do not accurately predict disease outcome of individual patients' prostate cancer. We used a rapid colorimetric in situ hybridization technique to evaluate the expression level of E-cadherin (which affects cell cohesion); matrix metalloproteinases (MMPs) types 2 and 9 (which affect invasion); and vascular endothelial growth factor/vascular permeability factor (which affects angiogenesis) in archival prostatectomy specimens from 40 patients. Intratumoral heterogeneity for gene expression (edge versus center versus perineural area) was more pronounced in advanced cancers than in those that were organ confined. Regardless of Gleason score, the highest expression level for E-cadherin was found in the center or perineural area of the tumors, whereas the highest expression levels for MMP-2 and MMP-9 were associated with the invasive edge. The relationship between advancing pathological stage and expression of all four metastasis-related genes was highly significant. Decreased expression of E-cadherin and increased expression of MMP-2, MMP-9, and vascular endothelial growth factor/vascular permeability factor were associated with the Gleason score of the tumors. Irrespective of serum prostate-specific antigen level or Gleason score, the ratio between expression of MMPs and E-cadherin at the invasive edge of tumors exhibited the strongest association with nonorgan-confined prostate cancer. These data suggest that the relative expression of metastasis-related genes in radical prostatectomy specimens can distinguish between organ-confined and advanced prostate cancers and provides the rationale for a prospective study correlating gene expression in pretherapy core biopsies with outcome.

Biopsy↗

PubMed1999

Limiting the location of a putative human prostate cancer tumor suppressor gene at chromosome 13q14.3.

We studied loss of heterozygosity (LOH) on human chromosome 13q in prostate cancer specimens to determine the location of a putative tumor suppressor gene (TSG) and to correlate these losses with the clinicopathological stage of the disease. Overall 13 (21%) of 61 specimens analysed had an allele loss on the long arm of chromosome 13. The most frequent (37%) LOH among the informative cases with allele losses was detected at the D13S284 locus on chromosome 13q14. 3. A portion of the DNA segment that spans this locus and is flanked by the microsatellite loci D13S153 and D13S163 was lost in 85% of the specimens with allele losses and was designated as a LOH cluster region (LCR). The LCR spans more than 6 Mbp of DNA. The results suggest that a TSG relevant for the development of prostate cancer is located telomeric to the RB locus. There was a significant correlation (P=0.0024) between chromosome 13q LOH and advanced metastatic disease, suggesting that loss of 13q14.3 region is associated with prostate cancer progression. However, further research must be conducted to establish the identity and function of this putative TSG.

Chromosome Mapping↗

PubMed1999

Relationship of Ki-67 labeling index to DNA-ploidy, S-phase fraction, and outcome in prostate cancer treated with radiotherapy.

BACKGROUND: Our purpose was to evaluate the relationship of Ki-67 labeling index (Ki67-LI) to deoxyribonucleic acid (DNA) ploidy, S phase fraction (SPF), other clinical prognostic factors, and clinical outcome for patients with prostate cancer treated by external beam radiotherapy. METHODS: Tissue was retrieved from 42 patients who underwent transurethral resection of the prostate before treatment with external beam radiotherapy between 1987-1993. DNA histogram profiles were classified as diploid (diploid + near-diploid) and nondiploid (tetraploid + aneuploid). Immunohistochemical staining of Ki-67 by the MIB-1 monoclonal antibody was used to calculate Ki67-LI. Median patient follow-up was 62 months. Treatment failure was defined as two consecutive rises in serum prostate-specific antigen (PSA) or clinical evidence of disease recurrence. RESULTS: The mean and median Ki67-LIs were 3.1 and 2.4, respectively (range, 0-12.4). Mean Ki67-LI values were significantly associated with higher stage, Gleason score, and pretreatment PSA. Nondiploid tumors had significantly higher Ki67-LIs, as did patients who failed radiotherapy over the follow-up period. SPF was not significantly correlated with Ki67-LI. As a categorical variable, the most significant relationships were seen when Ki67-LI was subdivided into thirds around the median (Ki67-LI </=1.5%, Ki67-LI >1.5-3.5%, and Ki67-LI >3.5%). This trichotomous variable correlated significantly with pretreatment PSA (P = 0.0008), tumor stage (P = 0.016), Gleason score (P = 0.024), and treatment failure (P = 0.0015), but not with DNA-ploidy (P = 0.15). In actuarial univariate analyses, Ki67-LI appeared to be a more significant predictor of patient outcome (P = 0.003) than DNA-ploidy (P = 0.035). CONCLUSIONS: The Ki67-LI correlated with known prognostic factors such as pretreatment PSA, tumor stage, and Gleason score, and was also weakly related to DNA-ploidy. In comparison to DNA-ploidy, Ki67 LI seems to be a better correlate of treatment outcome.

Aged↗

PubMed1999

Prophylaxis of acute renal allograft rejection using FTY720 in combination with subtherapeutic doses of cyclosporine.

BACKGROUND: In rodent transplant models, FTY720 exerts a synergistic affect with cyclosporine (CsA) to prolong allograft survival. The present experiments sought to test this combination in subhuman primates. METHODS: Cynomolgus monkeys were transplanted with kidney allografts that were incompatible in mixed lymphocyte culture reactions. The animals were treated with daily intramuscular injections of CsA using doses selected to maintain whole blood trough concentrations at therapeutic values between 40 and 200 ng/ml. The 4 experimental groups included CsA without or with 0.1, 0.3, or 1 mg/kg/day FTY720 delivered daily by intravenous bolus injection. Therapeutic effects were suggested both by the graft histology of biopsy within the first 10 posttransplant days and by the length of host survival. RESULTS: Whereas recipients treated with CsA alone rejected kidney allografts at a median survival time of 8.5 days (n=4), those treated with either 0.1 or 0.3 mg/kg/day FTY720 in addition to CsA showed significant prolongation of kidney allograft survival to 71 days (n=3; P<0.04) or 63 days (n=5; P<0.05), respectively. The hosts in the 1.0 mg/kg/day FTY720 group survived 48 days, with 2 of 5 recipients succumbing at 9 or 17 days postgraft, suggesting possible complications caused by overimmunosuppression. Biopsies of the 0.1 mg/kg/day FTY720 group on posttransplant day 7 documented mild to moderate rejection (grade I), indicated by multiple focal areas of tubular destruction. The histology results of transplants in the 0.3 or 1 mg/kg/day FTY720 group showed only minimal interstitial inflammatory infiltrates (borderline grade), with no evidence of tubular or arterial damage. Serum creatinine values among the animals in the 0.1 mg/kg/day FTY720 group showed increases in 2 of 3 recipients by day 20 and in the third by day 41 postgraft. Among the 0.3 mg/kg/day FTY720 group, 3 of 5 recipients maintained baseline creatinine values to 45 days postgraft; 1 recipient had stable kidney function for 120 days postgraft. CONCLUSIONS: Addition of FTY720 therapy to a subtherapeutic CsA immunosuppressive regimen delays the rejection of renal allografts in subhuman primates.

Acute Disease↗

PubMed1999

Galectin-1 and galectin-3 expression in human prostate tissue and prostate cancer.

Galectin-1 and galectin-3, two beta-galactoside-binding proteins, have been suggested to play a role in the development and progression of cancer. We have studied the expression of these molecules in normal human prostate tissue and prostate adenocarcinoma. Immunohistochemistry was used to examine formalin-fixed, paraffin-embedded sections of seven normal human prostates, eight cases of prostatic intraepithelial neoplasia (PIN), 20 primary adenocarcinomas of the prostate, and 12 prostate cancer metastases. Galectin-1 was expressed in most cases of all four histologic types. In contrast, galectin-3 expression was significantly decreased in primary carcinoma and metastatic disease compared with normal and premalignant tissue. Galectin-3 expression in primary tumors tended to be less than that of surrounding normal glands. We conclude that loss of galectin-3 expression may be associated with the progression of prostate cancer.

Adenocarcinoma↗