Treatment-related protein biomarker expression differs between primary and recurrent ovarian carcinomas.
ABSTRACT The molecular characteristics of recurrent ovarian cancers following chemotherapy treatment have been poorly characterized. Such knowledge could impact salvage therapy selection. Since 2008, we have profiled 168 patients' ovarian cancers to determine the expression of proteins that may predict chemotherapy response or are targets for drugs that are in clinical trials for ovarian cancer treatment. Expression of epidermal growth factor receptor (EGFR), HER2, VEGF, ER, c-Met, IGF1R, Ki67, COX2, PGP/MDR1, BCRP, MRP1, excision repair complementation group 1 (ERCC1), MGMT, TS, RRM1, TOPO1, TOP2A, and SPARC was measured by immunohistochemical analyses at Clinical Laboratory Improvement Amendments-certified laboratories. Our univariate analysis of 56 primary and 50 recurrent tumors from patients with advanced stage ovarian serous carcinoma revealed that PGP and ERCC1 were significantly upregulated in recurrent lesions (P < 0.05). To determine whether these or any of the other markers were differentially expressed in specimens obtained from the same individual at diagnosis and at recurrence, we analyzed 43 matched tumor specimens from 19 advanced stage ovarian carcinoma patients. We confirmed the expression differences in PGP and ERCC1 that were observed in the cohort analysis but discovered that the expression levels of BCRP, RRM1, and COX2 were also discordant in more than 40% of the matched tumor specimens. These results may have implications both for the use of biomarkers in therapy selection as well as for their discovery and validation. Expression of these and other candidate response biomarkers must be evaluated in much larger studies and, if confirmed, support the need for profiling of recurrent tumor specimens in future clinical trials.
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ABSTRACT: Among the gynecological malignancies, ovarian cancer is the leading cause of mortality in developed countries. Treatment of ovarian cancer is based on surgery integrated with chemotherapy. Platinum-based drugs (cisplatin and carboplatin) comprise the core of first-line chemotherapy for patients with advanced ovarian cancer. Platinum-resistant ovarian cancer can be treated with cytotoxic chemotherapeutics such as paclitaxel, topotecan, PEGylated liposomal doxorubicin, or gemcitabine, but many patients eventually relapse on treatment. Targeted therapies based on agents specifically directed to overexpressed receptors, or to selected molecular targets, may be the future of clinical treatment. In this regard, overexpression of folate receptor-α on the surface of almost all epithelial ovarian cancers makes this receptor an excellent "tumor-associated antigen". With appropriate use of spacers/linkers, folate-targeted drugs can be distributed within the body, where they preferentially bind to ovarian cancer cells and are released inside their target cells. Here they can exert their desired cytotoxic function. Based on this strategy, 12 years after it was first described, a folate-targeted vinblastine derivative has now reached Phase III clinical trials in ovarian cancer. This review examines the importance of folate targeting, the state of the art of a vinblastine folate-targeted agent (vintafolide) for treating platinum-resistant ovarian cancer, and its diagnostic companion (etarfolatide) as a prognostic agent. Etarfolatide is a valuable noninvasive diagnostic imaging agent with which to select ovarian cancer patient populations that may benefit from this specific targeted therapy.Pharmacogenomics and Personalized Medicine 01/2014; 7:31-42.
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ABSTRACT: Abstract Multidrug resistance presents one of the most important causes of cancer treatment failure. Numerous in vitro and in vivo data have made it clear that multidrug resistance is frequently caused by enhanced expression of ATP-binding cassette (ABC) transporters. ABC transporters are membrane-bound proteins involved in cellular defense mechanisms, namely, in outward transport of xenobiotics and physiological substrates. Their function thus prevents toxicity as carcinogenesis on one hand but may contribute to the resistance of tumor cells to a number of drugs including chemotherapeutics on the other. Within 48 members of the human ABC superfamily there are several multidrug resistance-associated transporters. Due to the well documented susceptibility of numerous drugs to efflux via ABC transporters it is highly desirable to assess the status of ABC transporters for individualization of treatment by their substrates. The multidrug resistance associated protein 1 (MRP1) encoded by ABCC1 gene is one of the most studied ABC transporters. Despite the fact that its structure and functions have already been explored in detail, there are significant gaps in knowledge which preclude clinical applications. Tissue-specific patterns of expression and broad genetic variability make ABCC1/MRP1 an optimal candidate for use as a marker or member of multi-marker panel for prediction of chemotherapy resistance. The purpose of this review was to summarize investigations about associations of gene and protein expression and genetic variability with prognosis and therapy outcome of major cancers. Major advances in the knowledge have been identified and future research directions are highlighted.Drug Metabolism Reviews 03/2014; · 5.54 Impact Factor
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ABSTRACT: The TP53 mutations have been proved to be predominated in ovarian cancer in a study from The Cancer Genome Atlas (TCGA). However, the molecular characteristics of recurrent ovarian cancers following initial treatment have been poorly estimated. This study was to investigate the pattern of somatic point mutations in matched paired samples of primary and recurrent epithelial ovarian cancers, using the OncoMap mutation detection protocol. We have adapted a high-throughput genotyping platform to determine the mutation status of a large panel of known cancer genes. OncoMap v.4.4 was used to evaluate genomic DNA isolated from a set of 92 formalin-fixed, paraffin-embedded (FFPE) tumors, consisting of matched paired samples of initially diagnosed and recurrent tumors from 46 epithelial ovarian cancer (EOC) patients. Mutations were observed in 33.7% of the samples, with 29.3% of these samples having a single mutation and the remaining 4.3% having two or more mutations. Among the 41 genes analyzed, 35 mutations were found in four genes, namely, CDKN2A (2.2%), KRAS (6.5%), MLH1 (8.2%) and TP53 (20.7%). TP53 was the most frequently mutated gene, but there was no correlation between the presence of mutation in any gene and clinical prognosis. Furthermore, somatic mutations did not differ between primary and recurrent ovarian carcinomas. Every mutation present in recurrent samples was detected in the corresponding primary sample. In conclusion, these OncoMap data of Korean EOC samples provide that somatic mutations were found in CDKN2A, KRAS, MLH1, and TP53. No differences in mutational status between primary and recurrent samples were detected. To understand the biology of tumor recurrence in epithelial ovarian cancer, more studies are necessary, including epigenetic modifications or additional mutations in other genes.PLoS ONE 01/2014; 9(6):e99451. · 3.73 Impact Factor