Since overexpression of the p53 protein due to genetic alterations may stimulate anti-p53 immune responses, serum p53 antibody responses have been observed in various types of cancers, including 15–16% of gastric cancers, 32.9% of esophageal cancers, and 30% of colorectal cancers [16, 23, 24]. The gene discussed is TP53; the disease is colorectal cancer.