Abstract
Background Nucleotide excision repair (NER) is pivotal in the development of smoking-related malignancies. We hypothesize that expression levels of NER proteins are associated with risk of the head and neck squamous cell carcinomas (HNSCCs) in a Chinese population. Methods To test this hypothesis, we conducted a case-control study of 337 HNSCC patients and 285 cancer-free controls by measuring the expression levels of nine core NER proteins in cultured peripheral lymphocytes. Results Compared with the controls, cases had statistically significantly lower expression levels of XPA (P=0.001). After dividing the subjects by controls’ medians of expression levels, we found an association between an increased risk of HNSCCs and low XPA expression levels [adjusted ORs and 95% CIs:1.42 and 1.03-1.96; Ptrend=0.031]. We identified a multiplicative interaction between smoking as well as drinking status and XPA expression levels (P = 0.005 and 0.044, respectively). Finally, the sensitivity of the expanded model with protein expression levels, in addition to demographic variables, on HNSCCs risk was significantly improved, especially among ever smokers and ever drinkers. Conclusions Reduced XPA expression levels were associated with an increased risk of HNSCCs in a Chinese population.
Associations between expression levels of nucleotide excision repair proteins in lymphoblastoid cells and risk of squamous cell carcinoma of the head and neck