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Background: Despite a reduction in the number of deaths from cancers made possible by the development of early detection tests, improvements in treatment, changes in the age distribution of the population, and changes of personal behaviors as a result of awareness, breast cancer remains a major health problem worldwide. Breast cancer is the most common cancer and second leading cause of cancer death in women. Several genetic and environmental factors are known to be involved in breast cancer pathogenesis, but its exact etiology is complicated and is not clearly identified. The structure and integrity of telomeres are pivotal for genome stability, and telomere length is maintained by the expression of the telomerase enzyme. The human telomerase reverse transcriptase (hTERT) gene is a principal functional subunit of the telomerase. Several recent studies have provided evidence that hTERT gene variants may have an important role in cancer development., Methods: Three hTERT variants (rs2736100, rs2736098, and rs2853669) were genotyped for 107 breast cancer patients and 110 healthy controls to determine their effect on breast cancer susceptibility., Results: It was observed that hTERT rs2736098 was associated with breast cancer risk (odds ratio [OR] = 1.88; p = 0.034), while rs2736100 and rs2853669 did not significantly differ between the groups., Conclusions: These findings are the first description of hTERT allele distributions in the Turkish population and may contribute to our understanding of breast cancer development. Nevertheless, further large-scale population studies are needed to understand the role of the hTERT polymorphisms and haplotypes in the development of breast cancer.

Colorectal cancer is an important cause of death throughout the world, and its etiology involves the interaction of genetic and environmental factors. Transporter proteins are important in protecting organs from xenobiotics or toxins. Organic anion-transporting polypeptide 1B1 (OATP1B1) plays role in hepatic uptake and clearance of albumin-bound amphipathic organic compounds, including endogen substances, drugs, or xenobiotics. The SLCO1B1 gene expressing OATP1B1 is highly polymorphic. Up to now, SLCO1BI variants were the focus of several investigations on drug pharmacokinetics and cancer susceptibility. However, no information has been available on association between SLCO1B1 and colorectal cancer risk. Therefore, the study aims to investigate the relationship between colorectal cancer and the functional common variants of SLCO1B1 (388 A>G, -11187 G>A, 521 T>C) and to estimate the prevalence of these variants in the Turkish population. To that end, the distributions of the variants were determined in 100 patients with colorectal cancer and 150 healthy volunteers. SLCO1B1 521 T>C was statistically significantly associated with colorectal cancer risk (odds ratio [OR]=2.66; 95% confidence interval [CI]=1.31-5.41; p=0.0057). In haplotype-based analysis, SLCO1B1 haplotype G(388)-T(11187)-T(521) might be associated with the development of colorectal cancer (OR=4.26; 95% CI=1.62-11.16; p=0.002). We believe that the findings may be beneficial to the development of efficacious preventive strategies and therapies for colorectal cancer.