Browsing by Author "Onrat S.T."

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    P53 intronic variant G13964C analyses in cases with colon cancer
    (2009) Onrat S.T.; Ellidokuz E.; Küpelioǧlu A.; Durhan E.
    Nucleotide alterations in p53 intron 6 have been reported to be associated with the dysregulation of p53 function and tumor development. G13964C base change functioned as dominant mutation similar to the more common missense, nonsense and splice-site mutations. To detect the G13964C variant PCR-RFLP assay was used. In this study, DNA was isolated from colon cancer tissue samples of 35 cases (19 female and 16 male) diagnosed to be colon carcinoma. In this study, we found that mutations were present in 30 (85.7%) of 35 cases enrolled into study. In 7 (23.3%) cases G/G, 21 (70.0%) cases G/C and 2 (6.7%) C/C genotypes were found. In 5 (14.3%) cases DNA isolation could not be obtained. Our results indicate that heterozygotes for the GC allele have higher frequency than other alleles and one of the reasons of colon cancer may be related to GC allele frequency.
  • No Thumbnail Available
    Item
    Frequency of TP53 codon72 polymorphism in cases with colon cancer
    (2009) Onrat S.T.; Ellidokuz E.; Küpelioǧlu A.; Durhan E.
    Recent studies indicated that the Arg allele is preferentially mutated and retained in various human cancers arising in Pro/Arg heterozygotes and it may be an important biomarker in colon cancer prognosis. In this study, DNA was isolated from paraffine-embedded colon tumor tissue samples of 35 cases diagnosed as colon carcinoma. We have observed PCR-RFLP genotyping for the codon 72 exon 4 polymorphism (Arg72Pro) of the p53 gene. In this study, we detected that TP53 codon 72 polymorphism was present in 27 (77.1%) of 35 cases enrolled into the study. In 14 (51.9%) cases Arg/Arg, 11 (40.7%) cases Arg/Pro and 2 (7.4%) cases Pro/Pro genotype frequencies were found. In 8 (22.9%) cases DNA isolation were not obtained. Our results point out that individuals homozygous for the Arg allele have higher frequency than other alleles and that colon cancer may be related to Arg allele frequency.
  • No Thumbnail Available
    Item
    Alterations of copy number of methylation pattern in mismatch repair genes by methylation specific-multiplex ligation-dependent probe amplification in cases of colon cancer
    (2011) Onrat S.T.; Çeken I.; Ellidokuz E.; Kupelioǧlu A.
    Genetic alterations and changes in genomic DNA cytosine methylation patterns are associated with all types of cancer and are caused by germline mutations in DNA mismatch repair (MMR) genes, predominantly MLH1 (MutL homolog 1, 19 exons) and MSH2 (MutS homolog 2, 16 exons). Genomic DNA was extracted from tissue samples embedded in paraffin from 49 patients with adenocarcinoma and from 21 patients with carcinoma for the study group; genomic DNA was extracted from lymphocytes from 10 healthy donors for the control group. We used methylation specific multiplex ligation-dependent probe amplification (MS-ML-PA), which allows the detection of copy number changes and unusual methylation levels of 10 to 50 different sequences in one reaction by use of the methylationsensitive restriction enzyme HhaI and sequence-specific capillary electrophoresis for the study of 24 genes.We found the mean methylation rates for MLH1 (97.14%), MSH2 (24.28%), MSH6 (MutS homolog 6) (67.14%), MSH3 (MutS homolog 3) (78.57%), MLH3 (MutL homolog 3) (75.71%), PMS2 (postmeiotic segregation increased 2) (65.71%), MGMT(O-6-methylguanine-DNA methyltransferase) (82.85%). We conclude that the mismatch repair (MMR) system is critical for the maintenance of genomic stability.