With hPEBP4 silencing combined with radiation, an obvious degradation of 116 kDa PARP into an 85 kDa fragmentation protein was observed compared with radiation only(Fig 3 E), confirming that hPEBP4 inhibits the radiation-induced apoptosis of rectal cancer cells, represented by activation of caspase-3 and proteolytic PARP cleavage. This evidence concerns the gene CASP3 and rectal cancer.