BIRC5 and colorectal cancer: Following up on the observation that the expression of survivin was inversely correlated with spontaneous and radiation-induced apoptosis [91], Rödel and colleagues used siRNA-mediated gene silencing to demonstrate that inhibition of survivin sensitizes colorectal cancer cells to radiation therapy, accompanied by increased levels of G2/M phase arrest and increased levels of DNA double-strand breaks after irradiation [92].