The vast majority (>91%) of human tumors with heterozygous TP53 (tumor protein p53) mutations spanning 32 cancer types, including colorectal cancer (CRC), undergo loss of the remaining wildtype (WT) TP53 allele (loss-of-heterozygosity, p53LOH) by mutation, chromosomal deletion, or copy-neutral loss-of-heterozygosity1–4. The gene discussed is TP53; the disease is colorectal cancer.