Mesenchymal stem cells expressing GD2 and CD271 correlate with breast cancer-initiating cells in bone marrow

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. Results: The percentages of BCIC (Aldefluor ⁺CD326⁺CD44⁺CD24^-) correlated with the percentages of BM-MSC, either CD45^-GD2⁺CD200 ⁺CD271⁺ (Kedall's τ = 0.684, p = 0.004) or CD45 ^-GD2⁺CD271⁺ in the bone marrow (Kedall's τ = 0.464, p = 0.042). 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 ⁺CD24^low/-, ALDH activity). BM-MSC was defined as CD34^-CD45^- cells that co-expressed GD2, CD271 and/or CD200 within CD326-depleted BM-MNC. 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.