title: Immunostaining of thymidylate synthase and p53 for predicting chemoresistance to S-1/cisplatin in gastric cancer.
abstract: High expression of thymidylate synthase (TS) and inactivation of p53 are allegedly associated with chemoresistance. The authors evaluated TS and p53 expression in gastric cancer treated with neoadjuvant S-1/cisplatin chemotherapy. Paraffin sections of pretreatment biopsy and surgical specimens from 41 gastric cancers were immunostained for TS and p53 protein after appropriate antigen retrieval. Fifty-one cases without neoadjuvant chemotherapy were also studied. In the pretreatment biopsies, high expression of TS was seen in 8% of the histologic responders, in 28% of the nonresponders and in 31% of the controls. High expression of p53 was observed in 56% of the nonresponders, but in 8% of the responders and in 29% of the controls (P<0.01 and P<0.05, respectively). The TS- and/or p53-high phenotype was seen in 76% of the nonresponders and in 54% of the controls, but in 8% of the responders (P<0.0001 and P<0.005, respectively). The data of the surgical specimens were consistent with those of the pretreatment biopsies. These results suggest that immunostaining for TS and p53 protein is useful for pretreatment selection of gastric cancer patients unresponsive to S-1/cisplatin chemotherapy.
authors.affiliation: Department of Pathology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan. skamo@fujita-hu.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Kamoshida
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: R
authors.initials: R
authors.lastname: Shimomura
authors.forename: Y
authors.initials: Y
authors.lastname: Sakurai
authors.forename: Y
authors.initials: Y
authors.lastname: Komori
authors.forename: I
authors.initials: I
authors.lastname: Uyama
authors.forename: Y
authors.initials: Y
authors.lastname: Tsutsumi
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002945:Cisplatin / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism / Q000601:surgery; D013940:Thymidylate Synthase / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D016159:Tumor Suppressor Protein p53; D013940:Thymidylate Synthase; D002945:Cisplatin