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.
Competing Interests: Disclosure The authors report no conflicts of interest in this work.