Carcinogenesis Advance Access originally published online on April 15, 2009
Carcinogenesis 2009 30(6):997-1002; doi:10.1093/carcin/bgp096
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Nucleotide excision repair core gene polymorphisms and risk of second primary malignancy in patients with index squamous cell carcinoma of the head and neck
1 Department of Head and Neck Surgery, University of Texas M. D. Anderson Cancer Center, Unit 441, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA
2 Bobby R. Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, TX 77030, USA
3 Department of Epidemiology, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA
* To whom correspondence should be addressed. Tel: +1 713 792 0227; Fax: +1 713 794 4662; Email: gli{at}mdanderson.org
The nucleotide excision repair (NER) pathway is central in response to damage induced by environmental carcinogens. Efficiency of this pathway, probably genetically determined, may modulate individual risk of developing squamous cell carcinoma of the head and neck (SCCHN) as well as second primary malignancy (SPM) after the index tumor. We hypothesized that common non-synonymous and regulatory single-nucleotide polymorphisms (SNPs) in the NER core genes individually, and more probably collectively, associated with the risk of SPM. We genotyped for seven selected SNPs in 1376 incident SCCHN patients who were prospectively recruited between 1995 and 2006 and followed for SPM development. We found that 110 patients (8%) developed SPM: 43 (39%) second SCCHN; 38 (35%) other tobacco-associated sites and 29 (26%) other non-tobacco-associated sites. The associations of these SNPs with SPM risk were assessed assuming a recessive genetic model. We did not find any significant associations of each or in combination of the seven SNPs with SPM risk in the recessive models. However, when we explored the combined effect based on an alternatively dominant genetic model, we found that the number of observed risk genotypes was associated with a significantly increased SPM risk in a dose-response manner (P = 0.005) and patients with five to seven risk genotypes had a significantly 2.4-fold increased SPM risk compared with patients with zero to two risk genotypes. These findings suggest that a profile of NER core gene polymorphisms might collectively contribute to risk of SPM not in a recessive model but in a dominant model among patients with an index primary SCCHN. These findings need to be validated in future studies with larger sample sizes and longer follow-up time.
Abbreviations: HPV, human papillomavirus; NER, nucleotide excision repair; SCCHN, squamous cell carcinoma of the head and neck; SNP, single-nucleotide polymorphism; SPM, second primary malignancy; XPC, xeroderma pigmentosum complementation group C
Received March 3, 2009; revised April 6, 2009; accepted April 12, 2009.