In addition, PELI1 knockdown significantly inhibited IR‐induced activation of apoptotic signaling pathways in TE‐1 and ECA‐109 tumor cells, which was reflected by the inhibition of the cleavage of caspase 9, caspase 7, caspase 3, and PARP (Fig. 3F). This evidence concerns the gene CASP3 and neoplasm.