Association of the microsatellite (GT)n repeat polymorphisms of the HO-1 gene promoter and corresponding serum levels with the risk of laryngeal squamous cell carcinoma

Conclusion: Long (GT)n repeat polymorphisms in the heme oxygenase-1 (HO-1) gene promoter and decreased serum HO-1 levels are associated with a higher susceptibility to laryngeal squamous cell carcinoma (LSCC). Objective: In this case-control study, the association of HO-1 microsatellite (GT)n repeat polymorphisms and serum levels with the risk of LSCC was investigated. Methods: A total of 142 LSCC patients, 54 vocal leukoplakia patients and 98 healthy controls, were examined for (GT)n polymorphisms by sequencing, and the serum HO-1 levels were detected in a sub-set from participants above by ELISA. Results: Compared with the controls, the LSCC group had significantly higher frequencies of L-allele (> 29 repeats) and L-allele carriers (p < 0.001, OR = 2.037 and p = 0.005, OR = 2.152, respectively). The frequencies of lymph node metastasis and of moderate or poor differentiation were significantly higher in L-allele carriers compared to non-L-allele carriers (p < 0.05). Significantly lower serum HO-1 levels were detected in LSCC patients (p < 0.001), and patients with lower serum HO-1 levels had more advanced cancer stage and a higher lymph node metastasis rate (p < 0.05). Furthermore, the L-allele carriers had lower serum HO-1 concentrations compared with the non-L-allele carriers (p = 0.019).