Our cell-based studies with c-Abl knockdown and inhibition and in vivo studies revealed that the anti-proliferation function for c-Abl in smooth muscle cells could be mediated by enhanced ERK1/2 activation, as ERK inhibitor U0126 not only suppressed smooth muscle cell proliferation but also the development of rectal prolapse in c-Abl deficient mice. This evidence concerns the gene ABL1 and Rectal prolapse.