TGFB1 and leiomyoma: In a co-culture system with human leiomyoma cells and uterine leiomyoma-derived fibroblasts, an increased secretion of TGF-β1 and TGF-β3 in the medium, an augmented number of leiomyoma cells and an elevated deposition of ECM proteins have been observed compared to a culture of human leiomyoma cells alone, highlighting the key role of soluble factors and of the ECM components in tumor progression [102].