Significance of CD44- and ALDH1-positive stem cells in сolorectal adenocarcinoma progression

Abstract

Aim – to analyze CD44 and ALDH1 immunohistochemical expression levels, as well as their correlations with proliferative and apoptotic activity of cancer cells in colorectal adenocarcinoma (CRA) of stages I–IV (pTNM).Materials and methods. Pathohistological and immunohistochemical studies of surgical material from 30 patients who underwent surgical treatment of colorectal adenocarcinoma (stages I–IV) were carried out.Results. It was established that colorectal adenocarcinoma is characterized by membranous and cytoplasmic CD44 expression in stromal cells (the area of immunopositive cells in CRA = 61.26 (42.58; 79.15) %), the area taken by the cells significantly increases during the tumor progression from stage I to stage III and directly correlates with the depth of the tumor invasion, as well as the presence of regional and distant metastases. Colorectal adenocarcinoma is characterized by cytoplasmic ALDH1 expression in the tumor stomal cells; the area of immunopositive cells in CRA = 40.22 (22.54; 47.77) % and significantly increases during the tumor progression from stage II to stage IV, as well as directly correlates with the depth of its invasion. Cytoplasmic ALDH1 expression in cancer cells of colorectal cancer was also revealed; the area of immunopositive cancer cells in CRA = 42.15 (32.06; 50.42) %. The area of immunopositive cancer cells significantly increases during the tumor progression from stage III to stage IV and directly correlates with each of the pTNM indexes. The correlation analysis of the indexes obtained for studied markers, as well as the markers of proliferation and apoptosis, made possible to reveal the next tendencies: the increasing area of CD44-possitive stromal cells in CRA is associated with decreasing cancer cells proliferation level, and also with the activation of epithelial-to-mesenchymal transition; the increasing area of ALDH1-possitive stromal cells is associated with decreasing cancer cells apoptosis level.Conclusions. The area of CD44-positive stromal cells significantly increases with the tumor progression from stage I to stage III and is associated with decreasing of the cancer cells proliferation level. The area of ALDH1-positive stromal cells significantly increases with tumor progression from stage II to stage IV and is associated with decreasing of the cancer cells apoptosis level, while the area of ALDH1-positive cancer cells significantly increases with tumor progression from stage III to stage IV.