CDC42 and carcinoma: Furthermore, in the co-cultures of carcinoma cells and stromal fibroblasts, the leading fibroblasts invade in an MMP-dependent manner and form tracks through α5-integrin-mediated RhoA activation and subsequent activation of myosin light chain (MLC), whereas carcinoma cells follow the tracks generated by the leading fibroblasts via Cdc42-mediated regulation of MLC [145].