title: Identification of colorectal cancer patients with tumors carrying the TP53 mutation on the codon 72 proline allele that benefited most from 5-fluorouracil (5-FU) based postoperative chemotherapy.
abstract: BACKGROUND
  Although postoperative chemotherapy is widely accepted as the standard modality for Dukes' stage C or earlier stage colorectal cancer (CRC) patients, biomarkers to predict those who may benefit from the therapy have not been identified. Previous in vitro and clinical investigations reported that CRC patients with wild-type p53 gene (TP53)-tumors benefit from 5-fluorouracil (5-FU) based chemotherapy, while those with mutated TP53-tumors do not. However, these studies evaluated the mutation-status of TP53 by immunohistochemistry with or without single-strand conformation polymorphism, and the mutation frequency was different from study to study. In addition, the polymorphic status at p53 codon 72, which results in arginine or proline residues (R72P) and is thought to influence the function of the protein significantly, was not examined.
  
  
  METHODS
  To evaluate the significance of the TP53 mutation as a molecular marker to predict the prognosis of CRC patients, especially those who received postoperative chemotherapy, we examined the mutation by direct sequencing from fresh CRC tumors and evaluated the R72P polymorphism of the mutated TP53 by a combined mutant allele- and polymorphic allele-specific polymerase chain reaction (PCR).
  
  
  RESULTS
  The TP53 mutation occurred in 147 (70%) of 211 Japanese CRC tumors. The mutation was observed in 93 (63%) tumors on the R72 allele and in 54 (37%) tumors on the P72 allele. Although the alterations to TP53 have no prognostic significance for CRC patients overall, we found that Dukes' stage C CRC patients who did not receive postoperative chemotherapy and carried the mutated TP53-R72 showed significantly longer survival times than those with the mutated TP53-P72 when evaluated by overall survival (p = 0.012).
  
  
  CONCLUSIONS
  Using a combined mutant allele- and polymorphic allele-specific PCR, we defined the codon 72 polymorphic status of the TP53 mutated allele in Japanese CRC patients. We raised a possibility that Dukes' stage C colorectal cancer patients with tumors carrying TP53 mutation, especially the P72 allele, benefited from 5-FU based postoperative chemotherapy.
authors: Department of Gastrointestinal Surgery, Kanagawa Cancer Center Hospital, 1-1-2 Nakao, Asahi-ku, Yokohama, Japan. godait@yokohama-cu.ac.jp
authors: Ten-i
authors: TI
authors: Godai
authors: Tetsuji
authors: T
authors: Suda
authors: Nobuhiro
authors: N
authors: Sugano
authors: Kazuhito
authors: K
authors: Tsuchida
authors: Manabu
authors: M
authors: Shiozawa
authors: Hironobu
authors: H
authors: Sekiguchi
authors: Akiko
authors: A
authors: Sekiyama
authors: Mitsuyo
authors: M
authors: Yoshihara
authors: Shoichi
authors: S
authors: Matsukuma
authors: Yuji
authors: Y
authors: Sakuma
authors: Eiju
authors: E
authors: Tsuchiya
authors: Yoichi
authors: Y
authors: Kameda
authors: Makoto
authors: M
authors: Akaike
authors: Yohei
authors: Y
authors: Miyagi
mesh_terms: D000368:Aged; D000483:Alleles; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000235:genetics; D017024:Chemotherapy, Adjuvant; D003062:Codon / Q000235:genetics; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D016158:Genes, p53; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011392:Proline / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D003062:Codon; D011392:Proline; D005472:Fluorouracil