Bowel cancer, genes and lifestyle

Lifestyle surpassed heredity in the prognosis of bowel cancer

Denis Strigun, Naked Science

Spanish scientists have concluded that lifestyle increases the risk of developing a malignant neoplasm of the large intestine to a greater extent than genetic mutations. The results of the work are published in the journal Scientific Reports (Ibáñez-Sanz et al., Risk Model for Colorectal Cancer in Spanish Population Using Environmental and Genetic Factors: Results from the MCC-Spain study).

According to statistics, more than 600 thousand new cases of colon cancer are detected annually in the world, and the disease is often diagnosed late. To be tested (immunochemical analysis for hidden blood in feces) is usually recommended for people over the age of 50 years. However, in this case, screening affects many people at low risk and at the same time does not always help to assess the condition of patients at high risk of cancer. The existing models for predicting such a risk are highly specific and are designed to study either phenotypic or genetic factors.

In a new paper, scientists from the Catalan Institute of Oncology and other institutions have built a prediction model that is based on a comprehensive assessment. To do this, they analyzed the results of the MCC study, which involved 10,183 patients in Spanish hospitals aged 20-85 years, whose sociodemographic signs were known. Part of the subjects (2171 people) had a positive diagnosis of malignant neoplasm of the large intestine. The authors also included 1,336 patients with bowel cancer and 2,744 healthy people in their sample, including data on their genotype.

To clarify the biomarkers of the disease, the researchers analyzed more than 200,000 genetic markers and 5,000 single nucleotide polymorphisms (SNPs) known from previous work. This made it possible to identify 21 SNPs most significantly associated with bowel cancer. According to the simulation, five polymorphisms (rs10752881, rs6983267, rs9929218, rs4939827, rs961253) correlated with pathology more strongly than the others, especially in combination with each other. Tobacco smoking was excluded from work because it slightly correlated with the risk of disease.

Environmental factors and family history were closely associated with the risk of bowel cancer. Thus, alcohol consumption, sedentary lifestyle, obesity, consumption of red meat (more than 65 grams per day), lack of vegetables (less than 200 grams per day) increase the probability of diagnosis. With age, the risk of the disease increases – up to three to six percent in men and up to two to four percent in women aged 50-69 years. For men, the risk of the disease is higher, but in the case of representatives of both sexes, the indicator shows an exponential increase after 50 years.

According to the authors, the new model has a high predictive ability, since it is based on a large amount of data on genetic and environmental factors of the disease. The role in the anamnesis of family history turned out to be remarkable. At the same time, how exactly this parameter affects the risk of neoplasm – due to heredity or a joint lifestyle – remains unclear.

Portal "Eternal youth" http://vechnayamolodost.ru  10.03.2017