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J Isola

Publications and source records attributed to J Isola.

At least 91 records · Page 5Linked to original sources
PubMed1995

In vivo amplification of the androgen receptor gene and progression of human prostate cancer.

Overexpression of amplified genes is often associated with the acquisition of resistance to cancer therapeutic agents in vitro. We have identified a similar molecular mechanism in vivo for endocrine treatment failure in human prostate cancer which involves amplification of the androgen receptor (AR) gene. Comparative genomic hybridization shows that amplification of the Xq11-q13 region (the location), is common in tumours recurring during androgen deprivation therapy. We found high-level AR amplification in seven of 23 (30%) recurrent tumours, but in none of the specimens taken from the same patients prior to therapy. Our results suggest that AR amplification emerges during androgen deprivation therapy by facilitating tumour cell growth in low androgen concentrations.

Aged↗
PubMed1995

Analysis of genetic changes underlying local recurrence of prostate carcinoma during androgen deprivation therapy.

The molecular mechanisms and genetic changes that lead to the progression of prostate cancer during endocrine therapy are poorly characterized. Here, paired specimens from both untreated primary tumors and from local recurrences were collected from 10 prostate cancer patients treated by conventional androgen deprivation therapy. The genetic progression of the tumors was studied by using interphase fluorescence in situ hybridization and chromosome-specific probes. Six primary tumors (60%) and all ten recurrent tumors were aneuploid by fluorescence in situ hybridization. The recurrent tumors also showed a high degree of chromosome copy number variability from one cell to another. Increased copy number of chromosome X was particularly common in the recurrent tumors. In addition, specific high level amplification of the androgen receptor (AR) gene (Xq12) was detected in three highly aneuploid recurrent tumors. Our findings suggest that hormone-refractory prostate cancers are genetically very complex and show intratumor genetic heterogeneity. Increased copy number of chromosome X and the amplification of the androgen receptor (AR) gene may confer proliferative advantage during androgen deprivation and thus contribute to the development of recurrence.

Androgen Antagonists↗
PubMed1995

Amplification of chromosomal region 20q13 in invasive breast cancer: prognostic implications.

Amplification of the chromosome 20q13 region was recently discovered in breast cancer by comparative genomic hybridization and subsequently further defined by fluorescence in situ hybridization with specific probes. The target gene of the amplification remains unknown. Here, fluorescence in situ hybridization with a cosmid probe for the minimal region of amplification (RMC20C001) was used to study 20q13 amplification in 132 primary breast carcinomas and 11 metastases. The size of the amplicon was studied with four flanking probes. Thirty-eight (29%) primary tumors and 3 (27%) metastases showed increased copy number of the RMC20C001 probe (>1.5-fold relative to the p-arm control). Nine (6.8%) of the primary tumors were highly (>3-fold) amplified. Although the size and location of the amplified region varied from one tumor to another, only the RMC20C001 probe was consistently amplified. 20q13 amplification was significantly associated with a high histological grade (P = 0.01), DNA aneuploidy (P = 0.01), and high S-phase fraction (P = 0.0085). High-level amplification was also associated with short disease-free survival of patients with node-negative breast cancer (P = 0.002). We conclude that high-level 20q13 amplification may be an indicator of poor clinical outcome in node-negative breast cancer and that this chromosomal region is likely to contain a gene with an important role in breast cancer progression. A large definitive study is warranted to assess the independent prognostic value of 20q13 amplification.

Adult↗
PubMed1994

Optimizing comparative genomic hybridization for analysis of DNA sequence copy number changes in solid tumors.

Comparative genomic hybridization (CGH) is a powerful new method for molecular cytogenetic analysis of cancer. In a single hybridization, CGH provides an overview of DNA sequence copy number changes (losses, deletions, gains, amplifications) in a tumor specimen and maps these changes on normal chromosomes. CGH is based on the in situ hybridization of differentially labeled total genomic tumor DNA and normal reference DNA to normal human metaphase chromosomes. After hybridization and fluorescent staining of the bound DNAs, copy number variations among the different sequences in the tumor DNA are detected by measuring the tumor/normal fluorescence intensity ratio for each locus in the target metaphase chromosomes. CGH is in particular useful for analysis of DNA sequence copy number changes in common solid tumors where high-quality metaphase preparations are often difficult to make, and where complex karyotypes with numerous markers, double minutes, and homogeneously stained chromosomal regions are common. CGH only detects changes that are present in a substantial proportion of tumor cells (i.e., clonal aberrations). It does not reveal translocations, inversions, and other aberrations that do not change copy number. At present, CGH is a research tool that complements previous methods for genetic analysis. CGH will advance our understanding of the genetic progression of cancer and highlight important genomic regions for further study. Direct clinical applications of CGH are possible, but will require further development and validation of the technique. We describe here our recent optimized procedures for CGH, including DNA labeling, hybridization, fluorescence microscopy, digital image analysis, data interpretation, and quality control, emphasizing those steps that are most critical. We will also assess sensitivity and resolution limits of CGH as well as discuss possible future technical improvements.

Chromosome Aberrations↗
PubMed1994

Overexpression of p53 and long-term survival in colon carcinoma.

Survival analysis of 144 histologically confirmed cases of colon carcinoma diagnosed in a 12 year period (1971-82) at the Tampere University Hospital was performed to test the hypothesis that p53 overexpression is associated with a poor clinical outcome. Immunohistochemical staining of paraffin-embedded sections using a polyclonal antibody CM-1 against p53 protein was performed to identify aberrant expression of the p53 tumour-suppressor gene. Sixty-nine per cent of the tumours (100/144) showed overexpression of the p53 protein. The prevalence of p53 overexpression was independent of age and sex of the patient and subsite of the tumour, but was slightly, although not statistically significantly, higher in advanced than in localised tumours. Overexpression was associated with a higher S-phase fraction. Some indication of a larger proportion of aneuploid tumours among those with overexpression was also observed, although this finding did not reach statistical significance. Significantly reduced patient survival for tumours with p53 overexpression was found. Patients with p53-overexpressing tumours had a corrected 5 year survival rate of 37% compared with 58% among patients whose tumours had normal expression of p53. The corresponding 10 year rates were 34% and 54%. In the multivariate analysis using a Cox model, the survival difference was independent of age and sex of the patient, as well as of subsite and stage of the tumour. Furthermore, the effect of p53 overexpression remained after controlling for flow cytometric parameters in an analysis of a subset of tumours. Thus, p53 overexpression appears to be a useful prognostic indicator in colon carcinoma.

Adolescent↗
PubMed1994

Prognostic variables in predicting pregnancy. A prospective follow up study of 907 couples with an infertility problem.

This report describes a prospective follow-up study on 907 infertile men presenting as partners of infertile couples. Couples who conceived were compared to those who remained infertile during a 3-year follow up. A univariate life table analysis showed that the duration of infertility, the age of both spouses, a history of male urethritis, the body mass index, the percentage of motile spermatozoa, the quality of motility, the motile sperm density, the total motile count, the sperm morphology, and the pH of semen were significant predictors of fertility. Another eleven socio-demographic and nine semen variables were not associated with fertility. Cox multiple regression analysis identified the duration of infertility, percentage total motility, the quality of motility combined, a history of male urethritis, the wife's age, and the morphology of the spermatozoa to be independent predictors of the reproductive outcome. A prognostic 'risk' ratio (chance for achieving pregnancy) was calculated as a function of these variables for each couple and a life table analysis was made between three classified subgroups of couples with different risk ratios. These life table curves make it possible to define the probability of an individual couple to achieve pregnancy at any given time.

Demography↗
PubMed1994

Molecular cytogenetics of human breast cancer.

Our studies of human breast cancer using CGH and FISH with precisely mapped probes have revealed a surprising amount of intratumor and intertumor heterogeneity in human breast cancers. However, some regions of abnormal copy number are found frequently. We believe that the regions of frequent abnormality harbor novel cancer genes, and that identification of these is important for diagnosis, prognostication, and the development of new therapies.

Breast Neoplasms↗
PubMed1994

Sources of variation in the assessment of cell proliferation using proliferating cell nuclear antigen immunohistochemistry.

The reproducibility in quantitation of proliferation activity, determined using the monoclonal antibody 19A2 to proliferating cell nuclear antigen (PCNA), was tested in visual and computer-assisted analyses of brain tumor material. The PCNA labeling index was scored using count (PCNA-LI, visual and computer analyses) and area (PCNA-LIa, computer analysis) estimates of immunopositivity. The quality of immunostaining was the most important reason for variation in the assessment results. Other significant variation sources in the assessment were experience in selecting microscopic fields and distinguishing immunopositive nuclei from immunonegative ones. Computer-assisted analysis improved the reproducibility of quantitation between different observers (visual rPCNA-LI = 0.624 versus computer assisted rPCNA-LI = 0.904). Also, the use of PCNA-LIa improved the intraobserver and interobserver reproducibility in different stainings (observer 1:rPCNA-LI = 0.857 versus rPCNA-LIa = 0.874; observers 1 and 2: rPCNA-LI = 0.904 versus rPCNA-LIa = 0.927; observers 3 and 4: rPCNA-LI = 0.848 versus rPCNA-LIa = 0.906). PCNA-LIa by computerized image analysis improves accuracy in the evaluation of the granularly expressed PCNA level. Furthermore, the effect of tumor heterogeneity on the assessment results can be diminished with the computerized method because large tissue areas can be analyzed faster.

Astrocytoma↗
PubMed1994

Analysis of changes in DNA sequence copy number by comparative genomic hybridization in archival paraffin-embedded tumor samples.

Analysis of previously unknown genetic aberrations in solid tumors has become possible through the use of comparative genomic hybridization (CGH), which is based on competitive binding of tumor and control DNA to normal metaphase chromosomes. CGH allows detection of DNA sequence copy number changes (deletions, gains, and amplifications) on a genome-wide scale in a single hybridization. We describe here an improved CGH technique, which enables reliable detection of copy number changes in archival formalin-fixed paraffin-embedded tumor samples. The technique includes a modified DNA extraction protocol, which produces high molecular weight DNA which is necessary for high quality CGH. The DNA extraction includes a 3-day digestion with proteinase K, which remarkably improves the yield of high molecular weight DNA. Labeling of the test DNA with a directly fluorescein-conjugated nucleotide (instead of biotin labeling) improved significantly the quality of hybridization. Using the paraffin-block technique, we could analyze 70 to 90% of paraffin blocks, including very old samples as well as samples taken at autopsy. CGH from paraffin blocks was highly concordant (95%) with analyses done from matched freshly frozen tumor samples (n = 5 sample pairs; kappa coefficient = 0.83). The method described here has wide applicability in tumor pathology, allowing large retrospective prognostic studies of genetic aberrations as well as studies on genetic pathogenesis of solid tumors, inasmuch as premalignant lesions and primary and metastatic tumors can be analyzed by using archival paraffin-embedded samples.

Chromosome Mapping↗
PubMed1994

Sensitive detection of chromosome copy number aberrations in prostate cancer by fluorescence in situ hybridization.

The pattern of chromosomal aberrations and their significance in prostate cancer are poorly understood. We studied 23 prostate cancer and 10 benign prostatic hyperplasia (BPH) specimens by fluorescence in situ hybridization (FISH) using pericentromeric repeat-specific probes for 10 different chromosomes. The aims of the study were: 1) to compare the sensitivity of FISH and DNA flow cytometry in aneuploidy detection, 2) to determine which chromosome copy number changes are most common, and 3) which probe combinations would be most effective in aneuploidy diagnosis. Disaggregated tumor cells from formalin-fixed, paraffin-embedded tissues were pretreated with our newly developed method based on hot glycerol solution to improve probe penetration. All BPH specimens were diploid by DNA flow cytometry and showed no numerical chromosome aberrations by FISH. In prostate cancer, flow cytometry showed abnormal DNA content in 35% of cases, whereas 74% were abnormal by FISH. Aberrant copy number of chromosomes 8 (48% of cases), X (43% of cases), and 7 (39% of cases) were most common. Ninety-four percent of all aneuploid cases would have been detected with these three probes alone. Simple chromosome losses were uncommon but in DNA tetraploid tumors relative losses (trisomy or disomy) of several chromosomes were often found, suggesting progression of prostate cancer through tetraploidization followed by losses of selected chromosomes. In conclusion, our results indicate that FISH using three selected chromosome-specific probes is two to three times more sensitive than flow cytometric DNA content analysis in aneuploidy detection.

Aneuploidy↗
PubMed1993

Localization of the glucocorticoid receptor in testis and accessory sexual organs of male rat.

Localization of glucocorticoid receptor-like immunoreactivity (GR-LI) was studied in adult rat testis, epididymis, ejaculatory duct, seminal vesicle and prostate by light and electron microscopic immunocytochemistry. In the interstitium of the testis GR-LI was seen in the nuclei of Leydig cells, macrophages, fibroblasts, smooth muscle cells and endothelial cells of blood vessels. Furthermore, GR-LI was observed in zygotene and early pachytene primary spermatocytes of some seminiferous tubules during stages XIII-XIV and I-III of the spermatogenic cycle. Other spermatogenic cells and Sertoli cells were devoid of staining. GR-LI was also found in peritubular myoid cells, fibroblasts and basal cells of the epididymis, vas deferens and prostate. Localization of GR-LI in primary spermatocytes and Leydig cells suggests that glucocorticoids directly affect spermato- and steroidogenesis in the testis. The absence of GR-LI from functional, stromal cells of the male accessory sexual organs suggests that they are not targets for glucocorticoid hormones.

Animals↗
PubMed1993

Cathepsin D expression detected by immunohistochemistry has independent prognostic value in axillary node-negative breast cancer.

PURPOSE: Increased expression of the lysosomal protease cathepsin D (CD) has been implicated in the metastatic progression of breast cancer. This study was designed to determine the prognostic significance of CD expression in axillary node-negative (ANN) breast cancer. The relationship of CD expression and onset of soft tissue recurrences and visceral metastatases was also studied. PATIENTS AND METHODS: We analyzed a population-based group of 262 ANN breast cancer patients, none of whom had received any adjuvant chemotherapy or endocrine therapy. An immunohistochemical method based on a new monoclonal antibody (1C11) with a distinct epitope specificity made it possible to study CD expression from archival paraffin-embedded specimens and to distinguish staining in tumor cells from the high-level expression found in tumor-infiltrating macrophages. RESULTS: High-level CD expression, as defined by cytoplasmic immunoreactivity in greater than 10% of the cancer cells, was found in 95 cases (36%). High-level CD expression was associated with large primary tumor size (P = .014), but not with histologic grade, estrogen and progesterone receptors, DNA index, or S-phase fraction, or with c-erbB-2 and p53 overexpression. Patients with CD-positive tumors developed significantly more often both soft tissue recurrences and visceral metastases (P = .0007) and had a significantly shorter disease-free survival (P < .0001). Eight-year overall survival of patients with high-level CD expression was 64% as compared with 90% in those with low-level expression (relative risk, 2.97; 95% confidence interval [Cl], 1.6 to 4.4; P < .0001). According to a Cox multivariate model and a regression-tree analysis, high-level CD expression was an independent predictor of poor overall survival in conjunction with tumor size and S-phase fraction. CONCLUSION: These results indicate that CD expression determined by immunohistochemistry is a powerful prognostic factor in ANN breast cancer. The most significant prognostic information was obtained when CD expression (predicting metastatic activity) was combined with estimate of cell-proliferation rate (S-phase fraction).

Adult↗
PubMed1993

Aberrant p53 expression in astrocytic neoplasms of the brain: association with proliferation.

Aberrant expression of the p53 suppressor gene was evaluated in 102 cases of astrocytic neoplasms. Immunohistochemical staining with a monoclonal antibody (DO-7) and a polyclonal antibody (CM-1) to p53 protein (both wild type and mutant) on formalin-fixed paraffin sections showed a strong correlation with malignancy grade. The staining was positive in 49% of malignant neoplasms (grades III and IV) and in 19 to 29% of grade II astrocytomas, whereas none of the grade I tumors were positive. p53 expression was significantly associated with proliferation rate determined by immunohistochemical proliferating cell nuclear antigen (PCNA)-staining (median PCNA-labeling index (%): 4.22 (DO-7-positive) versus 1.18 (DO-7-negative), P < 0.0001; 4.02 (CM-1-positive) versus 1.18 (CM-1-negative), P < 0.001). Interestingly, in the glioblastoma group (n = 44), p53-positive tumors had higher proliferation indices, suggesting that histologically similar tumors could be divided into prognostically different subgroups by immunohistochemical demonstration of aberrant p53 expression.

Analysis of Variance↗
PubMed1993

Atrophy and regeneration of rat calf muscles cause reversible changes in the number of nucleolar organizer regions. Evidence that also in nonproliferating cells the number of NORs is a marker of protein synthesis activity.

BACKGROUND: NORs are loops of DNA that transcribe to ribosomal RNA, and their number reflects the rDNA transcription, and, in this way, cell proliferation. EXPERIMENTAL DESIGN: The effect of muscle immobilization and remobilization on the number of nucleolar organizer regions (NORs) in the muscle cells and fibroblasts of rat calf muscles was studied histologically using a silver-staining technique (AgNOR). RESULTS: In muscle-cell nuclei, immobilization of 3 weeks produced a significant decrease in the number of AgNORs per nucleus. This phenomenon was reversible since, free remobilization of 4 weeks and especially intensified remobilization (free mobilization of 1 week plus treadmill running of 3 weeks) produced significant increase in the AgNOR counts. The treadmill running also produced a significant increase in the number of AgNORs in the muscle cells of contralateral (nonimmobilized) limbs. In intramuscular fibroblast nuclei, immobilization caused, in turn, a steady increase in the AgNOR count, the change being significant after 3 weeks. Free remobilization returned the count towards controls, and intensified remobilization returned it to the control level. CONCLUSIONS: Previous studies have shown that in the muscle cells immobilization decreases and remobilization (training) increases intracellular protein synthesis and that in the fibroblasts the opposite happens (immobilization increases and remobilization decreases intramuscular connective tissue formation). Our study gives indirect evidence that the number of NORs is a marker of ribosomal protein synthesis activity in non-proliferating cells. The cell-proliferation activity was proved to be zero using a proliferating-cell-nuclear-antigen technique.

Animals↗
PubMed1992

Association of overexpression of tumor suppressor protein p53 with rapid cell proliferation and poor prognosis in node-negative breast cancer patients.

BACKGROUND: Recent evidence indicates that a subset of axillary node-negative (ANN) breast cancer patients can benefit from adjuvant therapy. Reliable prognostic markers are needed, however, to help clinicians identify these patients and arrive at more rational treatment decisions. PURPOSE: Mutations of the p53 tumor suppressor gene often result in overexpression of the p53 protein. In this study, we evaluated the prognostic significance of p53 protein overexpression in patients with ANN breast cancer. We also studied the association between the tumor cell proliferation rate and overexpression of the p53 and c-erbB-2 proteins, both of which have been implicated in cell cycle control. The c-erbB-2 protein is the product of the ERBB2 gene. METHODS: Two hundred eighty-nine ANN cases were randomly selected from a population-based cohort of patients who had not received any kind of adjuvant chemotherapy or endocrine therapy. Overexpression of the p53 and c-erbB-2 proteins was studied immunohistochemically in archival paraffin-embedded tumor samples, using the CM-1 polyclonal and the TAb 250 monoclonal antibodies, respectively. The tumor cell proliferation rate was measured as the S-phase fraction by DNA flow cytometry. Statistical analyses were performed using BMDP software. RESULTS: High-level p53 protein overexpression, found in 41 of the 289 tumors, was most common in tumors with high histologic grade, negative estrogen receptor status, c-erbB-2 protein overexpression, DNA index greater than 1.3, or high S-phase fraction. The lowest S-phase levels were found in tumors with neither p53 nor c-erbB-2 protein overexpression; the highest levels were seen in tumors showing overexpression of both proteins (P less than .0001). Both p53 and c-erbB-2 overexpression, as well as tumor size, had independent prognostic value in multivariate analysis. Eight-year survival of patients with p53 protein overexpression was 56% compared with 81% in patients with no overexpression (relative risk, 3.7; P less than .0001). If the S-phase fraction was included in a Cox regression analysis, however, only the tumor size and the S-phase fraction emerged as independent predictors of survival. CONCLUSIONS: Overexpression of the p53 and c-erbB-2 proteins indicates a high malignant potential in ANN breast cancer, but it is not a significant prognostic factor independent of the cell proliferation rate. The correlation between overexpression of these proteins and an increased S-phase fraction suggests that they may confer a proliferative advantage to cancer cells in vivo.

Breast Neoplasms↗
PubMed1992

Small subgroup of aggressive, highly proliferative prostatic carcinomas defined by p53 accumulation.

BACKGROUND: Mutations in the p53 gene resulting in the accumulation of altered p53 proteins with prolonged half-life have been found in a large variety of human malignancies. PURPOSE: We studied the significance of p53 protein accumulation in prostatic carcinoma. METHODS: The material consisted of 137 paraffin-embedded, primary prostatic carcinomas. Accumulation of p53 protein was studied by immunohistochemical staining using a polyclonal p53-specific CM-1 antibody. Proliferation activity was determined by DNA flow cytometry and by immunohistochemical detection of proliferative cell nuclear antigen (PCNA) using a monoclonal PC10 antibody. RESULTS: Eight (6%) of the tumors showed intense p53 staining in more than 20% of the tumor cells, 15 (11%) had only lower level immunoreactivity, and 114 (83%) showed no staining. High-level p53 accumulation was associated with high histologic grade (P less than .001), DNA aneuploidy (P less than .05), and high cell proliferation rate as defined by flow cytometric S-phase analysis (P less than .01) or PCNA expression (P less than .01). High-level p53 accumulation predicted short, progression-free interval (P less than .01) and poor survival (P less than .001), with about a 12-fold relative risk of death as compared with p53-negative cases. Low-level p53 accumulation had no prognostic significance. CONCLUSIONS: Accumulation of p53 confers proliferative advantage for prostatic carcinoma cells and defines a small subgroup of highly malignant carcinomas.

Aged↗