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 CD44cells, 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 (=-0.470, <0.001, respectively and =-0.487, <0.001, respectively), also significant negative correlations between tissue CSCs and DFS and OS (=-0.548, <0.001, respectively and =-0.497, <0.001, respectively). Only the pathological grade (<0.004) and T stage (<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.