Consistent with the positive effect of MSCs on cancer cell growth, we have shown here that bone-marrow derived MSCs enhance the proliferation of a subset of metastatic prostate cancer cell lines, such as C4-2B, which of note is derived from in vivo LNCaP bone metastases and has endogenously elevated levels of STAT3 activity46. This evidence concerns the gene STAT3 and prostate carcinoma.