Pilot study on low penetrance breast and colorectal cancer predisposition markers in Latvia

Introduction: It has not been established whether CHEK2 and NOD2 variants are present in Latvia and whether inherited variation in these genes influences cancer risk in this population. Aim of the study: To evaluate the role of CHEK2 and NOD2 mutations in breast and colorectal cancers in the population of Latvia. Materials and methods: Peripheral venous blood samples were collected from 185 breast cancer and 235 colorectal cancer consecutive hospital-based cases from 11/2003 to 06/2005. The population control group included blood samples from the clamped distal part of the umbilical cord from 978 consecutive anonymous newborns born between 03/2005 and 08/2005. All cases and controls were tested for the presence of NOD2 3020insC mutation and CHEK2 I157T mutation. Results: NOD2 3020insC was present in 7.7% (18/235) of CRC cancers, in 9.2% (17/185) of breast cancers and in 7.7% (75/974) of controls. CHEK2 I157T variant was found in 7.6% (14/185) of breast cancer cases, 10.2% (24/235) of colon cancer cases and in 6.4% (63/978) of population controls. NOD2 3020insC variant was associated with increased risk of breast cancer (OR=2.5, p<0.05) for cases diagnosed at age between 51 and 60 years. CHEK2 I157T variant was associated with increased risk of colorectal cancer (OR=1.7, p<0.05) with the highest OR=2.0 for cases diagnosed at age >70 yrs. Conclusions: NOD2 3020insC and CHEK2 I157T variants may be associated with increased risk of colorectal and breast cancers in Latvia.