Biomedical subjects

Carlos Cordon-Cardo

Publications and source records attributed to Carlos Cordon-Cardo.

At least 109 records · Page 6Linked to original sources

PubMed2002

Neural network predicts sequence of TP53 gene based on DNA chip.

UNLABELLED: We have trained an artificial neural network to predict the sequence of the human TP53 tumor suppressor gene based on a p53 GeneChip. The trained neural network uses as input the fluorescence intensities of DNA hybridized to oligonucleotides on the surface of the chip and makes between zero and four errors in the predicted 1300 bp sequence when tested on wild-type TP53 sequence. AVAILABILITY: The trained neural network is available for academic use by contacting steen@cbs.dtu.dk

Base Sequence↗

PubMed2002

Impact of alterations affecting the p53 pathway in bladder cancer on clinical outcome, assessed by conventional and array-based methods.

This study was designed to define the potential clinical relevance of identifying alterations affecting p53 pathway in bladder cancer and to test a new, low-cost, high-throughput, and array-based TP53 sequencing technology. Tumor samples from 140 evaluable patients with bladder cancer were analyzed with two methods to detect TP53 gene mutations, including single-stranded conformational polymorphism followed by direct sequencing and an oligonucleotide array-based sequencing method. Immunohistochemistry was used to assess patterns of expression of p53, p21/WAF1, and mdm2. Median follow-up time was 27.6 months. Results from the above analyses were correlated with clinicopathological parameters and outcome. Combining the mutation-detection assays, 79 cases (56.4%) were found to harbor TP53 gene mutations. Direct sequencing identified 66 point mutations and five frameshift mutations. The p53 oligonucleotide array detected 65 point mutations and four splice site mutations in different exons but missed all five frameshift mutations. p53 nuclear overexpression was observed in 71 cases (50.7%), lack of p21 nuclear expression was found in 81 cases (57.9%), and mdm2 nuclear overexpression was seen in 64 cases (45.7%). In multivariate analysis, 17 patients (12.1%) had an altered p53 pathway, defined by the detection of mutant TP53 and/or p53 nuclear overexpression, loss of p21 nuclear expression, and mdm2 nuclear overexpression, and exhibited the worst clinical outcome in the observation period (P = 0.015), and it appears to be a significant prognostic factor associated with patient survival.

Cyclin-Dependent Kinase Inhibitor p21↗

PubMed2002

p63 expression profiles in human normal and tumor tissues.

PURPOSE: The p63 gene, located on chromosome 3q27-28, is a member of the p53 gene family. The product encoded by the p63 gene has been reported to be essential for normal development. EXPERIMENTAL DESIGN: In this study, we examined the expression pattern of p63 in human normal and tumor tissues by immunohistochemistry using a monoclonal antibody (clone 4A4) that recognizes all p63 splice variants, and by reverse transcription-PCR using isoform-specific primers. RESULTS: We found that p63 expression was restricted to the nucleus, with a nucleoplasmic pattern. We also observed that the expression was restricted to epithelial cells of stratified epithelia, such as skin, esophagus, exocervix, tonsil, and bladder, and to certain subpopulations of basal cells in glandular structures of prostate and breast, as well as in bronchi. Consistent with the phenotype observed in normal tissues, we found that p63 is expressed predominantly in basal cell and squamous cell carcinomas, as well as transitional cell carcinomas, but not in adenocarcinomas, including those of breast and prostate. Interestingly, thymomas expressed high levels of p63. Moreover, a subset of non-Hodgkin's lymphoma was also found to express p63. Using isoform-specific reverse transcription-PCR, we found that thymomas express all isoforms of p63, whereas the non-Hodgkin's lymphoma tended to express the transactivation-competent isoforms. We did not detect p63 expression in a variety of endocrine tumors, germ cell neoplasms, or melanomas. Additionally, soft tissue sarcomas were also found to have undetectable p63 levels. CONCLUSIONS: Our data support a role for p63 in squamous and transitional cell carcinomas, as well as certain lymphomas and thymomas.

Alternative Splicing↗

PubMed2002

Phase I trial of BCL-2 antisense oligonucleotide (G3139) administered by continuous intravenous infusion in patients with advanced cancer.

PURPOSE: To evaluate the safety and pharmacokinetics of BCL-2 antisense oligonucleotide (G3139) administered by prolonged i.v. infusion in patients with advanced cancer. EXPERIMENTAL DESIGN: A total of 35 patients was treated in cohorts of 3-6 with 0.6-6.9 mg/kg/day of BCL-2 antisense oligonucleotide as a continuous infusion for 14 or 21 days. Plasma levels of intact antisense oligonucleotide were measured in all patients. RESULTS: G3139 was generally well tolerated. At the highest dose level examined in this study (6.9 mg/kg/day), fatigue and transient reversible elevations of serum transaminases (grades 2-3) became apparent after >or=7 days of treatment. Both reactions were believed to be drug related. Pharmacokinetic analyses showed that steady-state plasma concentrations of G3139 were reached approximately 10 h after starting the infusion and increased linearly across the range of doses administered <or=6.9 mg/kg/day. The terminal plasma half-life was approximately 2 h. Exploratory studies using Western blots, performed on peripheral blood mononuclear cells on selected patients, demonstrated a decline in bcl-2 protein levels during treatment. No major antitumor responses were observed. CONCLUSIONS: BCL-2 antisense therapy is well tolerated. Relative to other dose-finding studies of G3139, fatigue was somewhat more prominent in this study, possibly because of the protracted i.v. infusion schedule of the antisense oligonucleotide. Current randomized trials are using the highest daily dose established in this study given by shorter infusion periods (i.e., 7 mg/kg/day for 5-7 days) to enhance the antitumor activity of standard cytotoxic drugs.

Adult↗

PubMed2002

Methylthioadenosine phosphorylase gene deletions are common in osteosarcoma.

PURPOSE: Methylthioadenosine phosphorylase (MTAP) is an enzyme essential in the salvage of cellular adenine and methionine synthesis. The MTAP gene is located in the 9p21 chromosomal region and its loss is frequently associated with deletion of the tumor suppressor genes p15(INK4b) and p16(INK4a). The aim of this study was to investigate the frequency of molecular alterations in MTAP in osteosarcoma. EXPERIMENTAL DESIGN: Samples from patients with high-grade osteosarcoma (n = 96) and three osteosarcoma cell lines (HOS, SaOS-2, and U2OS) were analyzed. Genomic DNA was analyzed for MTAP gene deletions by PCR, RNA expression was measured by semiquantitative reverse transcription-PCR, and the protein levels were measured by immunohistochemistry. RESULT: Deletion of at least one MTAP exon was found in 36 of 96 (37.5%) osteosarcoma patient samples and in one of the three cell lines (HOS). In all cases in which an MTAP gene deletion was observed, there was absence of detectable mRNA and protein. Furthermore, in four osteosarcoma patients, an MTAP deletion which was not evident at diagnosis was detected in subsequent tumor samples. CONCLUSIONS: The MTAP gene is commonly deleted in osteosarcoma patient samples, leading to an absence of mRNA and protein expression; these results indicate that inhibitors of de novo purine synthesis or methionine depletion may be effective as treatments for osteosarcoma patients whose tumors fail to express MTAP.

Adolescent↗

PubMed2002

17-Allylamino-17-demethoxygeldanamycin induces the degradation of androgen receptor and HER-2/neu and inhibits the growth of prostate cancer xenografts.

PURPOSE: Ansamycin antibiotics, including 17allylamino-17-demethoxygeldanamycin (17-AAG), inhibit Hsp90 function and cause the selective degradation of signaling proteins that require this chaperone for folding. Because mutations in the androgen receptor (AR) and activation of HER2 and Akt may account, in part, for prostate cancer progression after castration or treatment with antiandrogens, we sought to determine whether an inhibitor of Hsp90 function could degrade these Hsp90 client proteins and inhibit the growth of prostate cancer xenografts with an acceptable therapeutic index. EXPERIMENTAL DESIGN: The effect of 17-AAG on the expression of Hsp90 regulated signaling proteins in prostate cancer cells and xenografts was determined. The pharmacodynamics of target protein degradation was associated with the toxicology and antitumor activity of the drug. RESULTS: 17-AAG caused the degradation of HER2, Akt, and both mutant and wild-type AR and the retinoblastoma-dependent G1 growth arrest of prostate cancer cells. At nontoxic doses, 17-AAG caused a dose-dependent decline in AR, HER2, and Akt expression in prostate cancer xenografts. This decline was rapid, with a 97% loss of HER2 and an 80% loss of AR expression at 4 h. 17-AAG treatment at doses sufficient to induce AR, HER2, and Akt degradation resulted in the dose-dependent inhibition of androgen-dependent and -independent prostate cancer xenograft growth without toxicity. CONCLUSIONS: These data demonstrate that, at a tolerable dose, inhibition of Hsp90 function by 17-AAG results in a marked reduction in HER2, AR, and Akt expression and inhibition of prostate tumor growth in mice. These results suggest that this drug may represent a new strategy for the treatment of prostate cancer.

Androgens↗

PubMed2002

Antibody to vascular endothelial growth factor slows growth of an androgen-independent xenograft model of prostate cancer.

PURPOSE: Human tumors are dependent on angiogenesis for growth, and vascular endothelial growth factor (VEGF) is a major regulator of this process. We aimed to study clinical utility of a recombinant humanized monoclonal anti-VEGF antibody (rhu alpha VEGF) in the treatment of the CWR22R androgen-independent xenograft model of prostate cancer. EXPERIMENTAL DESIGN: rhu alpha VEGF has previously shown clinical activity in several xenograft cancer models. We administered 5 mg/kg rhu alpha VEGF i.p. twice weekly as a single agent and together with paclitaxel to established CWR22R xenografts. RESULTS: rhu alphaVEGF inhibited established tumor growth by 85% (P < 0.01 for trajectories of the average tumor volumes of the groups) at 3 weeks, but after cessation of rhu alpha VEGF treatment, tumor regrowth ensued. A paclitaxel dosage of 6.25 mg/kg s.c. five times/week slowed tumor growth (72% compared with controls at 3 weeks, P = 0.02). The combination of paclitaxel and rhu alpha VEGF resulted in greater inhibition of tumor growth than that observed with either agent alone (98% growth inhibition, P = 0.024 versus rhualpha VEGF alone and P = 0.02 versus paclitaxel alone). Paclitaxel alone had no antiangiogenic effects at the dosage studied, whereas rhu alpha VEGF had significant inhibition of angiogenesis, noted by microvessel density and CD34 staining. CONCLUSIONS: rhu alpha VEGF has cytostatic clinical activity in this androgen-independent prostate cancer xenograft model, and the addition of paclitaxel demonstrates increased clinical activity.

Androgens↗

PubMed2002

Comparative study of p63 and p53 expression in tissue microarrays of malignant melanomas.

p63 is a known homologue of p53. In contrast to p53, however, p63 mutations are rarely seen in tumours. There have been several reports that p63 plays a regulatory role in the normal differentiation of cells, whereas its role in tumour biology must still be elucidated. The main aim of this study was to compare p63 and p53 expression in tissue microarrays of malignant melanomas and to establish any prognostic significance. p63 expression was found in 2 out of 59 tumours, both pT4. The p63 index did not exceed 30%. p53 expression was found in 27 out of 59 melanomas, with maximal expression in up to 80% of tumour cells. There were no correlations observed between the two markers. Multivariate analysis confirmed the prognostically independent role of p53. This study also confirmed that tissue microarrays can be used effectively for evaluation of the expression of certain tumour markers.

Adult↗

PubMed2002

Tissue microarray molecular profiling of early, node-negative adenocarcinoma of the rectum: a comprehensive analysis.

PURPOSE: Early-stage adenocarcinoma of the rectum treated with curative intent has a favorable overall prognosis; however, 20%-30% of the patients recur, and the majority ultimately die of disease. Recurrence and tumor-related mortality may be attributable to molecular abnormalities in primary tumors accounting for their more aggressive biological behavior. This study evaluates such molecular phenotypes with regard to cell cycle regulation and proliferation and determines their significance for patient outcome. EXPERIMENTAL DESIGN: One hundred patients with primary T(2-3), N(0) adenocarcinoma of the rectum uniformly treated by surgery alone were studied. Core biopsies of pathological specimens were assembled on tissue microarrays, and expression of p53, mdm-2, p21, Bcl-2, p27, cyclin D1, and Ki-67 was analyzed by immunohistochemistry. Molecular profiles were correlated with disease-free (DFS) and disease-specific survival (DSS). RESULTS: Despite previously described prognostic relevance of some of the investigated molecules in analyses where different stages of colorectal cancer were included, none of the cell cycle-regulatory or proliferation-related markers was associated with recurrence or survival. However, patients with tumors demonstrating down-regulation of p27, a cyclin-dependent kinase inhibitor and tumor suppressor gene associated with development of metastases, showed a trend toward reduced DFS and DSS (P = 0.06 and P = 0.07, respectively). CONCLUSIONS: In this homogeneous group of patients with early-stage, node-negative adenocarcinoma of the rectum uniformly treated by surgery alone, the investigated cell cycle-regulatory and proliferation-associated proteins appear to have no prognostic significance. However, down-regulation of p27 appears to be associated with a trend toward reduced DFS and DSS, which suggests further investigation of other p27-related pathways potentially relevant for metastatic disease.

Adenocarcinoma↗

PubMedDate not supplied

Decreased expression of Ku70/Ku80 proteins in malignant melanomas of the oral cavity.

Ku70/80 are genes responsible for the repairing of DNA double-strand breaks and they function as a regulatory subunit of the DNA-dependent protein kinase. Their expression has not yet been investigated in malignant melanomas of the oral cavity. These tumours are characterized by very poor prognosis and etiology independent of UV-radiation. We investigated 29 malignant melanomas of the oral cavity for the expression of Ku70/80 proteins. Ku70 expression was preserved in 21 out of 29 tumours and the percentage of Ku70-positive cells did not exceed 76%. Ku80 was found in 19 out of 29 tumours and the percentage of Ku80-positive cells peaked at 62%. Correlations between Ku70 and Ku80 expression were lost (p>0.05). We conclude that decreased Ku70/80 expression in malignant melanomas of the oral cavity and loss of correlation between these markers may influence progression of oral melanomas.

Adult↗

PubMedDate not supplied

Relationship between DNA mismatch repair genes expression, Ku-genes expression and ploidy-related parameters in the progression of pigmented lesions of the skin.

Defects of DNA repair systems in cutaneous tumours are related to DNA mismatch repair genes (MLH1, MSH2, PMS1, PMS2) and Ku70/80 genes involved in double- strand repair. In this study we investigated the statistical relationship between these systems and DNA-ploidy-related parameters in 19 naevus cell naevi, 23 lentigos maligna, 76 primary melanomas and 31 melanoma metastases, applying the correlation coefficient according to Spearman. In naevi significant correlations were found between Ku70/80 gene expression and some ploidy-related parameters. In lentigos, additionally, some significant correlations between the expression of DNA mismatch repair genes were found. Similar results were demonstrated for primary melanomas. In metastases no one significant correlation between DNA mismatch repair genes and Ku-genes was present. We postulate that DNA mismatch repair genes and Ku70/80 genes are functionally independent and that some of them are able to influence ploidy-related parameters.

Adaptor Proteins, Signal Transducing↗

PubMedDate not supplied

Altered expression and new mutations in DNA mismatch repair genes MLH1 and MSH2 in melanoma brain metastases.

Brain metastases, including those of malignant melanoma (known for its high genomic instability), are the most common intracranial tumors. The main objective of this study was to investigate expression and mutation in the DNA mismatch repair system in melanoma brain metastases. Expression of MLH1, MSH2, PMS1 and PMS2 was investigated immunohistochemically in 31 melanoma metastatic tumors. Mutational analysis of MLH1 and MSH2 was performed in 17 melanoma brain metastases. Loss of MLH1 and MSH2 expression was found in 10/31 and 12/31 tumors. PMS1 (27/31) and PMS2 (28/31) expression was preserved in the majority of lesions. Potential missense mutation was found in MSH2 (exon 13) in 2/17 melanomas. Mutation in the intron sequence between exon 14 and 15 of MLH1 (exon 15) was observed in 4/17 cases. Our results indicate that the two major DNA mismatch repair genes, MLH1 and MSH2, are more frequently affected by alterations in the DNA mismatch repair system than the helper genes PMS1 and PMS2. The presence of mutations of MSH2 and MLH1 in melanoma brain metastases, which has not been found in primary melanomas, indicates the high genomic instability of melanoma brain metastases.

Adaptor Proteins, Signal Transducing↗

PubMedDate not supplied

Cytokeratin positivity in paraffin-embedded malignant melanomas: comparative study of KL1, A4 and Lu5 antibodies.

The unclear role of cytokeratin (CK) in the progression and diagnostics of malignant melanomas stimulated us to compare the reactivity of three antibodies directed to CK in 109 paraffin-embedded melanomas. By far the majority of melanomas did not express cytokeratin even at the<1% level, only vimentin. In about 6% of melanomas it was possible to find CK expression ranging between 3 and 40% of melanoma cells. There was a correlation between CK expression and pT-stage. Cytokeratin-expressing tumours were found in the more advanced pT-stages. The independent prognostic values of none of the three CK antibodies investigated could be shown.

Adult↗

PubMedDate not supplied

Cytokeratin expression correlates with aneuploidy in cytological specimens of melanoma metastases.

It has been postulated that the high malignancy of melanomas could be connected with an increased cytokeratin (CK) expression. In order to define the relationship between CK expression and genetic instability of melanoma metastases, ploidy-related parameters were compared in cytological specimens of CK-positive and CK-negative melanoma metastases. CK expression was investigated immunohistochemically in 35 melanoma liver metastases and in 52 melanoma lymphatic metastases. Ploidy-related parameters were evaluated on Feulgen-stained specimens with a CAS200 image analyzer. Cytokeratin was detected in 14 out of 35 melanoma liver metastases and in 24 out of 52 melanoma lymphatic metastases investigated. Significant differences between CK-positive and CK-negative melanoma metastases were found for the percentage of diploid cells, percentage of tetraploid cells, percentage of aneuploid cells between 4c and 8c, as well as for 5c exceeding rate. Our results confirmed that CK is present in more advanced (unstable), clearly aneuploid forms of melanoma metastases.

Adult↗

PubMedDate not supplied

Relationship of nm23 expression to proliferation and prognosis in malignant melanomas of the oral cavity.

Twenty-nine cases of oral melanomas were investigated for nm23 and Ki67 antigen expression, as well as for the fraction of tumour cells in S-phase, using immunohistochemical techniques and DNA cytophotometry. Nm23 expression was significantly reduced and Ki67 antigen expression increased in primary tumours with either lymph node or organ metastases in comparison to tumours without metastases. The percentages of Ki67 immunoreactive tumour cells and cells in S-phase correlated positively with each other and negatively with the percentage of nm23-expressing cells. These data argue against a significant growth stimulatory function of the nm23H1 gene product nucleoside diphopshate kinase in the progression of oral melanomas. The functional relevance of nm23 in relation to increased proliferation and metastatic spread is discussed.

Adult↗

PubMedDate not supplied

Proposal of a new grading system for malignant fibrous histiocytomas.

The proposed grading system for malignant fibrous histiocytomas (MFH) comprises 3 grades of malignancy. Analogous to other grading systems, the system includes the factors of mitotic rate and necrosis. In addition to these two factors, the concept of cellularity was included. The prognostic relevance of the grading systems published by Costa, Coindre, van Unnik, Pezzi and Tsujimoto as well as the grading system proposed by the present study was tested on 161 MFH. The results showed that all grading systems tested produced clearly significant differences (p < 0.01) with regard to the survival estimated for patients with various grades of malignancy. These results revealed the superiority of systems that use 3 grades of malignancy over a 2-grade classification. The proposed grading system yielded a lower percentage of grade II tumours (37%) than the grading systems of Coindre (60%) and van Unnik (70%). In the multivariate analysis of all grading systems, the proposed grading system was the only one to show prognostic relevance (p < 0. 05).

Adolescent↗

PubMedDate not supplied

Altered expression of DNA double-strand repair genes Ku70 and Ku80 in carcinomas of the oral cavity.

The relevance of double-strand DNA repair genes has been demonstrated in several tumours. The main aim of this study was to analyse the expression of the heterodimers Ku70 and Ku80, building regulatory subunits of the DNA-dependent protein kinase in 40 oral carcinomas. Ku70 expression was found in 87.5% of grade 1 and grade 3 tumours and in 82.9% of grade 2 carcinomas. Ku80 presence was noted in 87.5% of grade 1 tumours, 82.9% of grade 2 tumours and in all grade 3 tumours. Ku70-positive cells were present in 90.5% of tumours without and in 80% of tumours with lymphatic metastases. A similar relationship was found for Ku80 expression. Additionally, the expression of Ku70 was highly significantly related to smoking habits. Our results demonstrated that defects of DNA double-strand repair genes play an important role in the tumour progression of oral carcinomas.

Adult↗

PubMedDate not supplied

Analysis of DNA mismatch repair gene expression and mutations in thyroid tumours.

Alterations of DNA mismatch repair genes, primarily demonstrated in hereditary nonpolyposis colorectal carcinomas, were reported to be of relevance for the progression of several sporadic tumours. In this study, the expression and mutations of MLH1, MSH2, PMS1 and PMS2 in a panel of thyroid tumours, including nodular hyperplasia, follicular adenomas and carcinomas, were investigated. The expressions of MLH1, MSH2 and PMS1 were generally higher in malignant tumours than in benign lesions (p < 0.01). This observation can find potential diagnostic application in the differentiation of follicular adenomas from follicullar carcinomas of the thyroid. No point mutations in the DNA mismatch repair genes MSH2 (exon 12, 13) and MLH1 (exon 15, 16) were found.

Adaptor Proteins, Signal Transducing↗