Prognostic and predictive value of thymidylate synthase expression in colon cancer
ABSTRACT Thymidylate synthase (TS) is an enzyme responsible for DNA synthesis. Its competitive inhibition constitutes the major mechanism of the antitumor effect of 5-fluorouracil (5-FU) therapy, which significantly improves the survival rate of colon cancer patients. The aim of our study was to examine the clinical importance of TS expression in colon cancer patients and to correlate its expression with various clinicopathological parameters, tumor proliferative capacity, cell cycle-related molecules' expression and patients' survival. Of the 71 colon cancer patients studied, 51 (71.8%) tested positive for TS, with the positive result being statistically significantly correlated with patients' gender (P = 0.012), tumor histological grade (P = 0.032), vascular invasion (P = 0.017) and the expression of cyclin E, pRb and p16 (P = 0.042, P = 0.001 and P = 0.001, respectively). The overall 5-year survival rate was 40% for TS-positive patients and 68.6% for TS-negative ones (P = 0.0134); in patients aged >70 years, this was 30 and 77.8%, respectively (P = 0.0008). In a multivariate analysis of survival, TS expression proved to be of prognostic significance (P = 0.0174). Our findings support evidence for the clinical importance of TS expression in colon cancer patients and define it as an independent prognostic risk factor.
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ABSTRACT: 5-Fluorouracil (5-FU) is the most commonly used therapeutic agent for colon cancer treatment. Several studies have evaluated in patients with colon cancer, either the role of genes involved in the 5-FU pathway, such as thymidylate synthase (TS), thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) or the role of microsatellite instability (MSI) as prognostic or predictive markers for adjuvant chemotherapy efficacy, with discordant results. In this study we investigated the combined effect of TS, TP, DPD mRNA expression and MSI status in primary tumors of patients with colon cancer, all treated with 5-FU adjuvant therapy. TS, TP and DPD expression levels were investigated by real-time quantitative RT-PCR on RNA extracts from formalin-fixed and paraffin-embedded tissues of 55 patients with colon adenocarcinoma. In the same case study MSI status was assessed on DNA extracts. A higher TS expression was significantly associated with a longer survival for patients with cancers of stage II (P < 0.01), but not for those with stage III (P = 0.68). In addition, in multivariate analysis, a higher TS expression was significantly associated with a decreased risk of death (HR 0.13, 95% CI 0.03-0.59, P < 0.01), while the MSI status did not have effects on patients' survival. This retrospective investigation suggests that TS gene expression at mRNA level can be a useful marker of better survival in patients (especially of those with cancers of stage II) receiving 5-FU adjuvant chemotherapy, independently of the MSI status.Journal of Cancer Research and Clinical Oncology 04/2010; 137(2):201-10. DOI:10.1007/s00432-010-0872-1 · 3.01 Impact Factor
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ABSTRACT: Apoptosis is a tightly regulated process that plays a critical role in many biological events. Members of the BCL2 (Bcl-2) family of apoptosis-related genes have been found to be differentially expressed in various malignancies and have been proposed as prognostic tumor biomarkers. We have recently discovered and cloned a new member of the BCL2 gene family, BCL2L12, expressed in colon tissues. Here we have investigated expression of the BCL2L12 gene in colon cancer tissues and assessed its prognostic value. Total RNA was isolated from 96 specimens of malignant colon tissue. After testing the RNA quality, cDNA was prepared by reverse transcription. A highly sensitive real-time PCR method for BCL2L12 mRNA quantification was developed using SYBR Green chemistry. GAPDH served as a housekeeping gene. Relative quantification analysis was performed using the comparative C(T) method (2(-DeltaDeltaCT)). High BCL2L12 expression levels were found in smaller (< or =5 cm, p=0.027) and well-differentiated tumors (p=0.034), as well as in early-stage tumors (p=0.039). Survival analysis demonstrated that patients with BCL2L12-positive colon tumors have significantly longer disease-free survival and overall survival (p=0.015 and p=0.027, respectively). Our results suggest that BCL2L12 gene expression may represent a potential new biomarker for colon cancer.Biological Chemistry 10/2008; 389(12):1467-75. DOI:10.1515/BC.2008.173 · 2.69 Impact Factor
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ABSTRACT: The protective effects of iodine on breast cancer have been postulated from epidemiologic evidence and described in animal models. The molecular mechanisms responsible have not been identified but laboratory evidence suggests that iodine may inhibit cancer promotion through modulation of the estrogen pathway. To elucidate the role of iodine in breast cancer, the effect of Lugol's iodine solution (5% I(2), 10% KI) on gene expression was analyzed in the estrogen responsive MCF-7 breast cancer cell line. Microarray analysis identified 29 genes that were up-regulated and 14 genes that were down-regulated in response to iodine/iodide treatment. The altered genes included several involved in hormone metabolism as well as genes involved in the regulation of cell cycle progression, growth and differentiation. Quantitative RT-PCR confirmed the array data demonstrating that iodine/iodide treatment increased the mRNA levels of several genes involved in estrogen metabolism (CYP1A1, CYP1B1, and AKR1C1) while decreasing the levels of the estrogen responsive genes TFF1 and WISP2. This report presents the results of the first gene array profiling of the response of a breast cancer cell line to iodine treatment. In addition to elucidating our understanding of the effects of iodine/iodide on breast cancer, this work suggests that iodine/iodide may be useful as an adjuvant therapy in the pharmacologic manipulation of the estrogen pathway in women with breast cancer.International journal of medical sciences 07/2008; 5(4):189-96. · 1.55 Impact Factor