RESUMEN
Objective: Targeted deep sequencing was used to characterize the mutational spectrum of APC in Chinese colorectal tumors in comparison to that in Caucasians from The Cancer Genome Atlas (TCGA) and to investigate whether APC mutations can predict overall survival in CRC patients receiving adjuvant chemotherapy.Methods: A total of 315 Chinese CRC patients including 241 stage II/III patients receiving fluorouracil-based adjuvant chemotherapy were included in this study. Next generation sequencing was carried out to detect somatic mutations on all APC exons. The associations between APC mutations and overall survival were determined by the Cox proportional hazards model.Results:APC was mutated in 221 of 315 colorectal tumors (70.2%). Chinese CRC had a much higher frequency of missense mutations (16.2% vs. 2.4%), but a lower frequency of nonsense (41.0% vs. 54.2%) and frameshift mutations (10.5% vs. 18.4%) than Caucasian CRC. Among stage II/III patients receiving fluorouracil-based adjuvant chemotherapy, APC mutations showed a significant association with worse survival (HR = 1.69; 95% CI, 1.10-2.62; p = .0179). Of the mutation types, frameshift mutations conferred the highest risk of death (HR = 2.88; 95% CI, 1.54-5.37; p =.0009). Among individual mutation sites, Arg232Ter, the most frequent mutation in Chinese CRC, exhibited the strongest negative impact on survival (HR = 2.65; 95% CI, 1.16-6.03; p =.0202).Conclusion:APC overall mutation was an independent predictor for overall survival of stage II/III CRC patients receiving fluorouracil-based chemotherapy.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon , Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias Colorrectales , Fluorouracilo , Proteína de la Poliposis Adenomatosa del Colon/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Quimioterapia Adyuvante , China , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Fluorouracilo/administración & dosificación , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mutación , Estadificación de Neoplasias , PronósticoRESUMEN
AIM: To investigate the predictive value of PIK3CA and TP53 mutation status in colorectal cancer (CRC) patients treated with 5-fluorouracil-based chemotherapy. METHODS: In this study, a total of 315 patients with histologically proven CRC were enrolled from Yangpu Hospital affiliated to Shanghai Tongji University between 2007 and 2011. Of these patients, 241 with stage II/III CRC received 5-fluorouracil-based adjuvant chemotherapy. Formalin-fixed paraffin-embedded lesion samples of the patients with curatively resected CRC were collected. Next-generation sequencing was performed to identify somatic gene mutations. The correlation of PIK3CA and TP53 mutation status with overall survival (OS) was analyzed using a Cox proportional hazard model and the Kaplan-Meier method. RESULTS: Among the 241 patients with stage II/III in this cohort, the PIK3CA and/or TP53 mutation was detected in 177 patients, among which 54 patients had PIK3CA and TP53 double mutations. The PIK3CA or TP53 mutation was not significantly correlated with OS in univariate and multivariate analyses. Compared with patients without PIK3CA and TP53 mutations, those with double PIK3CA-TP53 mutations showed a significantly worse survival (univariate HR = 2.21; 95%CI: 1.15-4.24; multivariate HR = 2.02; 95%CI: 1.04-3.91). The PIK3CA mutation located in the kinase domain showed a trend toward a shorter OS compared with wild-type tumors (multivariate HR = 1.56; 95%CI: 1.00-2.44; P = 0.052). The Kaplan-Meier curve showed that patients harboring the PIK3CA mutation located in the kinase domain had a worse clinical outcome than those with wild-type status (Log-rank P = 0.041). CONCLUSION: Double mutation of PIK3CA and TP53 is correlated with a shorter OS in stage II/III CRC patients treated with 5-fluorouracil-based therapy.