Serrated adenomas of the colon: from histological picture to molecular and genetic pathogenesis

Aim. To study the clinical, morphological and molecular genetic characteristics of serrated formations of colorectal localization.Materials and methods. The study included 73 patients aged from 28 to 84 years with 92 serrated colon formations, who underwent colonoscopy with biopsy. The average age of men is 64.5 years, for women – 54.7 years. Next, a morphological, immunohistochemical and molecular genetic study was carried out.Results. According to histological examination, sessile serrated adenomas (SSA) of the colon were most often found (47.5 %), hyperplastic polyp (HP) and traditional serrated adenoma (TSA) were found less frequently and with the same frequency (25.4 % each). The most typical location for SSA was the right half of the colon, for TSA – the left. HP was determined evenly in both halves of the colon. An immunohistochemical study of the subtypes revealed no significant differences in the expression of markers. In 50 % of SSA, a mutation in the BRAF gene was detected, 41.7 % of HP had a genetic mutation of BRAF, 16.6 % had a mutation of KRAS. In 58.4 % of TSA, a KRAS mutation was detected, in 8.3 % – BRAF, and in 33.3 % there was no gene mutation.Conclusion. As a result of our study, it was found that the types of serrated adenomas have significant differences depending on the gender and age of the patients, as well as on the DNA structure. In addition, they differ in molecular genetic characteristics.