Cancer stem cells in metastatic lymph nodes in patients with colorectal cancer

Objective. To assess the content of cancer stem cells (CSCs) with the EpCAMhighCD44+ phenotype in metastatic lymph nodes in patients with colorectal cancer (CRC), as well as the expression of CD133, CD166, CD24, and CD184 on their surface. Materials and methods. A cross-sectional prospective study of the cellular composition of metastatic lymph nodes was performed in 123 patients with phase III CRC. The control group consisted of 87 patients who underwent surgery for non-neoplastic colon diseases. Lymph node cells were isolated by an enzymatic method. The expression of CD45, EpCAM, CD44, CD133, CD166, CD184, and CD24 on CSCs was assessed by flow cytometry using a CytoFLEX LX cytometer (Beckman Coulter, USA). Statistical analysis of the data was performed using the nonparametric Mann–Whitney U test. Results. Among metastatically affected regional lymph nodes of CRC patients, 7.6 [4.3; 11.9]% of CSC with the EpCAMhighCD44+ phenotype were found in the total population of non-lymphoid cells (CD45-). No cells with high EpCAM expression were found in the lymph nodes of patients in the control group. In metastatic lymph nodes, 50.8 [42.5; 60.1]% of CSC simultaneously express CD133 and CD166, and 49.2 [39.9; 57.5]% of cells exhibited the presence of the CD133 antigen. All CSCs in metastatic lymph nodes expressed CD184, and 94.9 [90.0; 97.7]% of them simultaneously contained CD24. Conclusion. Highly EpCAM-expressing CSCs can be found in metastatically affected regional lymph nodes in patients with stage III colorectal cancer. CD44-positive cells comprise 7.6% of nonlymphoid cells. The CXC type 4 chemokine receptor (CD184) and CD133 protein are markers of CSCs in CRC.