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  • Küçük Resim
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    Gene Methylation of SFRP2, P16, DAPKI, HIC1, and MGMT and KRAS Mutations in Sporadic Colorectal Cancer
    (Elsevier Science Inc, 2010) Pehlivan, Sacide; Artaç, Mehmet; Sever, Tuğçe; Bozcuk, Hakan; Kılınçarslan, Can; Pehlivan, Mustafa
    The aim of this study was to investigate the methylation of the SFRP2, P16, DAPK1, HIC1, and MGMT genes, as well as the mutation of amino acid codons 12 and 13 of the KRAS gene in normal and tumor tissue DNA of patients diagnosed with sporadic colorectal cancer (SCRC). The methylation of gene regions and the KRAS mutations of normal (N) and tumor tissue (T) DNA obtained from 17 patients diagnosed with SCRC and 20 healthy controls were investigated using the polymerase chain reaction and reverse-hybridization methods. There was an Asp mutation in four patients, an Asp and Ser mutations in one patient in codon 12 of the KRAS gene, and an Asp mutation in codon 13 in eight patients. Overall promoter methylation (OPM) in the SFRP2 gene was observed in one N and four T, whereas partial promoter methylation (PPM) was observed in two N and five T. OPM in the P16 gene was present in one T. In the DAPK1 gene, OPM existed in seven T and five N, while PPM was present in two N. In the HIC1 gene, OPM was demonstrated in three T, while PPM was noted in two N; however, no methylation existed in N. In the MGMT gene, OPM occurred in five T and two N, and PPM was present in one T. KRAS mutations in Turkish patients with SCRC are similar to those of other population groups. Methylations in the genes, which underwent methylation analysis, were higher in Tin comparison with N, and it has been suggested that significant results would be obtained by making a study with a larger population.
  • Küçük Resim Yok
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    The value of XPD and XRCC1 genotype polymorphisms to predict clinical outcome in metastatic colorectal carcinoma patients with irinotecan-based regimens
    (SPRINGER, 2010) Artaç, Mehmet; Bozcuk, Hakan; Pehlivan, Sacide; Akcan, Songül; Pehlivan, Mustafa; Sever, Tuğçe; Özdoğan, Mustafa
    Previous studies have suggested that DNA repair enzyme polymorphisms may bear prognostic value in metastatic colorectal carcinoma (MCRC). We prospectively treated 43 MCRC patients with irinotecan-based regimens (XELIRI or IFL). Allelic variants of the XRCC1 gene at codon 399 and XPD gene at codon 751 were analyzed in lymphocyte DNA by PCR-RFLP. Clinical outcome variables: overall survival (OAS), progression-free survival (PFS) and the occurrence of grade 3 or 4 hematological and gastrointestinal (GIS) toxicities were evaluated. In the univariate analysis for OAS (n = 43) only XPD and XRCC1 polymorphisms were significant (P = 0.05 and P = 0.04, respectively). After adjustment for performance status (ECOG = 0, 1 vs. 2) and disease extent (single vs. multiple metastatic site), XRCC1 genotype and performance status retained significance (HR = 2.85, P = 0.04, and HR = 3.19, P = 0.02, respectively). Gln/Gln genotype was associated with the greatest risk of death. Type of presentation (metastatic vs. local disease at first presentation) was the only significant predictor of PFS in the univariate analysis (n = 40, P = 0.003). After adjustment for performance status and disease extent, type of presentation retained its significance (HR = 4.35, P = 0.003). None of the toxicities was associated with these genotypes. XRCC1 genotype independently predicted overall survival in metastatic colorectal carcinoma patients treated with irinotecan-based chemotherapy.