CDKL2 and breast cancer: Interestingly, two human bone marrow derived mesenchymal stem cells (MSC-1 and -2), human lung fibroblast WI-38 and immortalized human foreskin fibroblast BJ-hTERT+LT also expressed CDKL2 at a much higher level than epithelial breast cancer lines with an average fold change of 26.5 (Fig. 7A).