Our previous studies have demonstrated a combined predictive value of p53 and p21 for tumor regression after preoperative nRT in rectal carcinoma patients and identified that ATP-binding cassette subfamily C member 4 (ABCC4) may play a role in response to irradiation of CRC cell line HT29 in vitro[4]–[5]. This evidence concerns the gene TP53 and rectal carcinoma.