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S100A16 is a conserved member of the S100 protein family in mammals. Its upregulation was observed in many tumors and is related to malignant transformation. In this study, we explored the independent prognostic value of S100A16 in terms of overall survival (OS) and recurrence-free survival (RFS) by performing a retrospective study, using data in The Cancer Genome Atlas (TCGA)-lung adenocarcinoma (LUAD). Besides, by using deep sequencing data in TCGA-LUAD, we also explored the association between S100A16 expression and its DNA methylation and copy number alterations (CNAs). Results showed that the primary LUAD tissues (N = 514) had significantly elevated S100A16 expression compared with the normal lung tissues (N = 59). Based on OS data of 502 primary LUAD cases, we found that high S100A16 expression was correlated with inferior OS. The following univariate and multivariate analysis confirmed that increased S100A16 expression was an independent prognostic indicator of unfavorable OS (HR: 1.197, 95%CI: 1.050–1.364, p = 0.007) and RFS (HR: 1.206, 95%CI: 1.045–1.393, p = 0.011). By examining the DNA methylation data in TCGA-LUAD, we found that some S100A16 DNA CpG sites were generally hypermethylated in normal tissues, but not in LUAD tissues. Regression analysis identified a moderately negative correlation between S100A16 expression and its DNA methylation. In comparison, although DNA amplification (+1/+2) was frequent (378/511, 74%) in LUAD patients, it was not associated with increased S100A16 expression. Based on findings above, we infer that aberrant S100A16 expression might be modulated by its DNA hypomethylation and serves as an independent prognostic indicator of unfavorable OS and RFS in LUAD. [ABSTRACT FROM AUTHOR]

EGFR inhibitors, even with therapeutics superiorities in anticancer, can cause idiosyncratic pulmonary and hepatic toxicities that are associated with the reactive electrophile bioactivated by Cytochrome P450s (P450s). Until now, neither has the electrophilic intermediate been caught experimentally, nor has the subtle mechanism been declared. Herein, the underlying mechanism of bioactivation mediated by P450s was explored by DFT calculations for a case of EGFR inhibitor, Erlotinib. Based on the calculation and analysis, we suggest that with other metabolites, reactive electrophiles of Erlotinib: epoxide and quinine-imine, can be generated by several steps along the oxidative reaction pathway. The generation of epoxide needs two steps: (1) the addition of Erlotinib to Compound I (Cpd I) and (2) the rearrangement of protons. Whereas, quinine-imine needs a further oxidation step (3) via which quinone is generated and ultimately turns into quinine-imine. Although both reactive electrophiles can be produced for either face-on or side-on pose of Erlotinib, the analysis of energy barriers indicates that the side-on path is preferred in solvent environment. In the rate-determining step, e.g. the addition of Erlotinib to the porphyrin, the reaction barrier for side-on conformation is decreased in aqueous and protein environment compared with gas phase, whereas, the barrier for face-on pose is increased in solvent environment. The simulated mechanism is in good agreement with the speculation in previous experiment. The understanding of the subtle mechanism of bioactivation of Erlotinib will provide theoretical support for toxicological mechanism of EGFR inhibitors. [ABSTRACT FROM AUTHOR]

Background: BRAF mutation has been investigated as a prognostic factor in metastatic colorectal cancer (mCRC) undergoing anti-EGFR monoclonal antibodies (moAbs), but current results are still inconclusive. The aim of this meta-analysis was to evaluate the relationship between BRAF mutation status and the prognosis of mCRC patients treated with moAbs. Methods: Eligible studies were identified by systematically searching Pubmed, the Cochrane Library, Web of Knowledge, and OVID. Risk ratio (RR) for overall response rate (ORR), Hazard ratios (HRs) for Progression free survival (PFS) and Overall survival (OS) were extracted or calculated. Prespecified subgroup analyses were conducted in KRAS wild-type and in different study types. The source of between-trial variation was explored by sensitivity analyses. Quality assessment was conducted by the Hayden’s criteria. Results: A total of twenty one trials including 5229 patients were identified for the meta-analysis. 343 patients displayed BRAF mutations of 4616 (7.4%) patients with known BRAF status. Patients with BRAF wild-type (WT) showed decreased risks of progression and death with an improved PFS(HR 0.38, 95% confidence intervals 0.29–0.51) and an improved OS (HR 0.35 [0.29–0.42]), compared to BRAF mutant. In KRAS WT population, there were even larger PFS benefit (HR 0.29[0.19,0.43]) and larger OS benefit (HR 0.26 [0.20,0.35]) in BRAF WT. A response benefit for BRAF WT was observed (RR 0.31[0.18,0.53]) in KRAS WT patients, but not observed in unselected patients (RR 0.76 [0.43–1.33]). The results were consistent in the subgroup analysis of different study types. Heterogeneity between trials decreased in the subgroup and explained by sensitivity analysis. No publication bias of ORR, PFS and OS were detected. Conclusions: The results indicate that BRAF mutant is a predictive biomarker for poor prognosis in mCRC patients undergoing anti-EGFR MoAbs therapy, especially in KRAS WT patients. Additional large prospective trials are required to confirm the predictive role of BRAF status. [ABSTRACT FROM AUTHOR]