Study of genetic detection of KRAS, FCGR, CYP3A5 and CYP1A1 in predicting clinical outcomes of chemotherapy/target therapy in metastatic colorectal cancer (mCRC) / 中国医师杂志

ABSTRACT

Objective To investigate the predictive and prognostic value of genetic detection of Kirsten rat sarcoma viral oncogene homolog(KRAS),Fc gamma receptors (FCGR),cytochrome P450 3A5 (CYP3A5) and CYP1A1 in patients with metastatic colorectal cancer (mCRC) receiving C225 combined with CapeOx chemotherapy.Methods Twelve KRAS wild-type (WT) mCRC patients were selected receiving C225 (cetuximab) combined with CapeOx (capecitabine/oxaliplatin) chemotherapy.KRAS,FCGR,CYP3A5,CYP1 A1 gene mutation were detected before treatment.The expressions of phosphatase and tensin homolog deleted on chromosome ten (PTEN) were detected in colorectal cancer tissues and the corresponding adjacent tissues expression with immunohistochemical staining (SP method).The relationship between FCGR,CYP3A5,CYP1A1 mutation,and PTEN expression and survival time were analyzed.Results The mutation rates of FCGR,CYP3A5,and CYP1 A1 were 16.7％ (2/12),25％ (3/12) and 16.7％ (2/12) in 12 patients with KRAS WT,respectively.PTEN was expressed mainly in the nucleus in yellowish brown.The rates of expression in the tissue adjacent to the cancer and in the tumor tissue were 100％ (12/12) and 41.7％ (5/12),respectively.PTEN expression in tumor tissue was reduced or absent.The study indicated that the objective response rate [complete response + partial response (CR + PR)] was 80％ in patients whose KRAS,FCGR,CYP3A5,and CYP1A1 were all in wild type,the CR + PR rates in FCGR,CYP3A5,and CYP1A1 gene mutation group were 0,33.6％ and 50％.The objective response rates of patients with PTEN expression or null were 50％ and 37.5％,respectively (P ＜ 0.05).The progression free survival (PFS) with KRAS/FCGR/CYP3A5/CYP1A1 wild type or mutation were 15.56 or 8.12 months (P ＜ 0.05).The overall survival (OS) with wild type or mutation of KRAS/FCGR/CYP3A5/ CYP1A1 were 25.03 or 19.21 months(P ＜0.05).The PFSs of positive or negative expression of PTEN in patients were 9.13 or 7.87 months (P ＜0.05),and the OSs of positive or negative expression of PTEN in patients were 24.25 or 18.74 months (P ＜0.05).Conclusions FCGR,CYP3A5 and CYP1A1 mutations and PTEN expression null both have been associated with resistance to cetuximab in mCRC patients.FCGR,CYP3A5,CYP1A1 and PTEN can be served as the predictive biomarkers for the response to cetuximab.