ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Being in line with authors who described BCR-ABL positive macrophages contaminating in vitro cultures of stromal cells from BM of CML patients, Wὃhrer et al., 2007 showed that the abnormal stromal function in CML might in fact be due to the presence of BCR-ABL positive macrophages in the marrow microenvironment which may contribute to selective expansion of leukemic hematopoietic cells [16].