Purpose: The bone marrow microenvironment is considered a critical component in the dissemination and fate of cancer cells in the metastatic process. We explored the possible correlation between bone marrow mesenchymal stem cells (BM-MSC) and disseminated breast cancer-initiating cells (BCIC) in primary breast cancer patients.
Experimental design: Bone marrow mononuclear cells (BM-MNC) were collected at the time of primary surgery in 12 breast cancer patients. BM-MNC was immunophenotyped and BCIC was defined as epithelial cells (CD326+CD45-) with a "stem-like" phenotype (CD44+CD24low/-, ALDH activity). BM-MSC was defined as CD34-CD45-cells that co-expressed GD2, CD271, and/or CD200 within CD326-depleted BM-MNC.
Results: The percentages of BCIC (Aldefluor+CD326+CD44+CD24-) correlated with the percentages of BM-MSC, either CD45-GD2+CD200+CD271+ (Kedall's tau = 0.684, p = 0.004) or CD45-GD2+CD271+ in the bone marrow (Kedall's tau = 0.464, p = 0.042).
Conclusions: There was a positive correlation between mesenchymal stem cells expressing GD2 and CD271 and breast cancer-initiating cells in BM of patients with primary breast cancer.