Pretreatment detection of circulating and tissue CD133 + CD44 + cancer stem cells as a prognostic factor affecting the outcomes in Egyptian patients with colorectal cancer

Background and aim: Colorectal cancer is one of the most common malignant tumors worldwide. As CD133 and CD44 are notable markers of cancer stem cells (CSCs) identity, it is thought to be a predictive indicator for colorectal cancer. The aim of this study was to investigate the cell cycle state of CD133+ CD44+ and CD133- CD44-cells, isolated from primary human colorectal tumors, and to assess the clinical impact of CD133+ CD44+ CSCs on patients' outcome regarding disease-free survival (DFS) and overall survival (OS). Materials and methods: Tissue samples were collected from 50 primary colorectal cancer patients. Flow cytometric analysis was performed to isolate tissue CD133+ CD44+ CSCs and CD133- CD44- tumor cells from primary colorectal cancer tissue to compare the cell cycle of both types of cells. Also circulating CSCs were assessed by flow cytometry. Results: Higher percentage of tissue CD133+ CD44+ CSCs isolated from colorectal cancer patients was found in G0/G1 phase. However, tissue CD133- CD44- tumor cells were predominantly found in the S phase; there were significant negative correlations between tissue CD133+ CD44+ CSCs and DFS and OS (r=-0.470, P<0.001, respectively and r=-0.487, P<0.001, respectively), also significant negative correlations between tissue CSCs and DFS and OS (r=-0.548, P<0.001, respectively and r=-0.497, P<0.001, respectively). Only the pathological grade (P<0.004) and T stage (P<0.004) had a significant effect on circulating CSC counts. Conclusion: Tissue CD133+ CD44+ CSCs were more quiescent than tissue CD133- CD44- tumor cells and both circulating CSCs and tissue CSCs were considered independent negative prognostic factors on OS and DFS.