Telomere length, genetic variants and gastric cancer risk in a Chinese population

Telomeres maintain chromosomal stability and integrity and are crucial in carcinogenesis. Telomere length is implicated in multiple cancer risk, but the results are conflicting. Genome- wide association studies have identified several genetic loci associated with telomere length in Caucasians. However, the roles of telomere length and related variants on gastric cancer development are largely unknown. We conducted a case- control study including 1136 gastric cancer cases and 1012 controls to evaluate the associations between telomere length, eight telomere length- related variants identified in Caucasians and gastric cancer risk in Chinese population. We observed an obvious U- shaped association between telomere length and gastric cancer risk (P < 0.001), with odds ratios (95% confidence intervals) being 3.81 (2.82- 5.13), 1.65 (1.21- 2.26), 1.28 (0.93- 1.77) and 1.78 (1.30- 2.44) for individuals in the first (the shortest), second, third and fifth (the longest) quintile as compared with those in the fourth quintile as reference group. The weighted genetic score (WGS) of eight variants was significantly associated with telomere length (P < 0.001), and in particular, the G allele of rs2736100 in TERT at 5p15.33 exhibited a significant association with long telomeres (P = 0.047). However, we did not observe significant associations between these genetic variants and gastric cancer risk for both single- variant and WGS analyses. These findings suggest that either short or extreme long telomeres may be risk factor for gastric cancer. Genetic variants identified in Caucasians may also contribute to the variation of telomere length in Chinese but seems not to gastric cancer susceptibility.