Meta-analysis of associations between the TP53 Arg72Pro polymorphism with risk of head and neck carcinomas based on case-control studies

Genetic determinants in head and neck squamous cell carcinoma and their influence on global personalized medicine

While sequencing studies have provided an improved understanding of the genetic landscape of head and neck squamous cell carcinomas (HNSCC), there remains a significant lack of genetic data derived from non-Caucasian cohorts. Additionally, there is wide variation in HNSCC incidence and mortality worldwide both between and within various geographic regions. These epidemiologic differences are in part accounted for by varying exposure to environmental risk factors such as tobacco, alcohol, high risk human papilloma viruses and betel quid. However, inherent genetic factors may also play an important role in this variability. As limited sequencing data is available for many populations, the involvement of unique genetic factors in HNSCC pathogenesis from epidemiologically diverse groups is unknown. Here, we review current knowledge about the epidemiologic, environmental, and genetic variation in HNSCC cohorts globally and discuss future studies necessary to further our understanding of these differences. Long-term, a more complete understanding of the genetic drivers found in diverse HNSCC cohorts may help the development of personalized medicine protocols for patients with rare or complex genetic events.

Association of the p53 or GSTM1 polymorphism with the risk of nasopharyngeal carcinoma: A meta-analysis

p53 and glutathione S-transferase M1 (GSTM1) are the most popular suppressor genes. Several previous studies demonstrated positive associations of these gene polymorphisms with numerous cancer types, including hepatocellular cancer, while the association between p53/GSTM1 polymorphisms and the nasopharyngeal carcinoma (NPC) risk was inconsistent and underpowered. However, no studies investigating the combinational effect of these two genes on NPC risk were performed. To confirm the effects of p53 and GSTM1 polymorphisms on the risk of NPC, a meta-analysis of all the available previous studies associating p53 and GSTM1 with the risk of NPC was performed. A comprehensive search of PubMed, Web of Science and SD database until November 2014 was performed to identify the relevant studies. The data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Meta-regression and subgroup analyses were performed to identify the source of heterogeneity. Finally, five studies with 1,419 cases and 1,707 controls were included for the p53 polymorphism and three studies with 837 cases and 1,299 controls were included for the GSTM1 polymorphism. Regarding p53, a significantly increased NPC risk was observed in the overall population (C vs. G, OR, 1.245; 95% CI, 1.045-1.483; P=0.014; additive models: CC vs. GG, OR, 1.579; 95% CI, 1.100-2.265; P=0.013 and CG vs. GG, OR, 1.230; 95% CI, 1.039-1.456; P=0.016; dominant model, OR, 1.321; 95% CI, 1.127-1.549; P=0.001; recessive model, OR, 1.429; 95% CI, 1.017-2.009; P=0.040). Concerning GSTM1, a significantly increased NPC risk was observed in the overall population (null versus non-null, OR, 1.282; 95% CI, 1.075-1.530; P=0.006). In the subgroup analyses stratified by the source of controls, a significant association of p53 with NPC risk was also demonstrated, while no association with GSTM1 was observed. Therefore, the p53 G72C polymorphism may have a susceptible role in the carcinogenesis of NPC, while genetic deletion of GSTM1 may contribute to increased susceptibility to NPC. Further large and well-designed studies are required to confirm this association.