CD34 and melanoma: In a pioneering study, Kaplan et al. (2005) showed that lung metastasis by B16 melanoma was preceded by increased production of fibronectin by resident fibroblast-like stromal cells followed by α4β1 dependent adhesion of VEGFR1+ (CD133+, CD117+, CD34+) hematopoietic bone marrow myeloid progenitors.