Comparative segmental molecular genetic assessment of colorectal cancer in the community of endoscopy and surgery of a multidisciplinary hospital

The aim of the study was to compare the frequency of segmental detection of colon cancer during routine endoscopy with the results of surgical treatment of tumor intestinal obstruction together with paired molecular genetic analysis of CRC and the mucous membrane of the index segment of the colon from the standpoint of studying precancerous changes. Material and methods. In a continuous cross-sectional retrospective study, the results of 3086 colonoscopies and 63 surgical protocols of patients with tumor intestinal obstruction were studied. In a prospective study, 401 cell samples were studied: colon cancer - 118, index segment mucosa - 114, normal mucosa - 169. The relative expression levels of 9 miRNA markers associated with the development of CRC were determined: miR-135b-5p, -141-3p, -143-3p, -200a-3p, -20a-5p, -21-5p, -31-5p, -34a-5p, -92a-3p, small nuclear RNA U6, as well as miRNA-16-5p and -191-5p. The mRNA of the following genes was also assessed: MUC2, CDX2, NOX1, LGR5, SMAD4, MS4A12, TIMP1, Ki-67, TERT with normalization to the housekeeping genes PGK1 and PUM1. Results. The overall frequency of CRC detection during colonoscopy was 4.93% (152 cases). During colonoscopy and surgical interventions, cancers of the left half of the colon prevailed. The expression levels of miRNA and mRNA in tumors between colon segments vary significantly, which may hide some patterns, but allows us to talk about the uniqueness of each segment of the colon. The same expression levels in the index mucosa and in cancers were found for miRNA-200a in the ascending colon, for miRNA-21 in the rectum, for miRNA-34a and LGR5 in the left half. Tumors of different segments of the colon turned out to be heterogeneous in the studied mutations, however, there is no such diversity in the mucosa of different segments of the colon. Conclusion. The obtained results allow us to speak about the necessity of searching for precancerous changes during colonoscopy.