The Val allele of HER-2 codon 655 predicts the progression of oral squamous cell carcinoma

HER-2 proto-oncogene is important for oral carcinogenesis. HER-2 codon 655 polymorphism, either isoleucine (Ile: ATC) or valine (Val: GTC), was associated with the risk of breast carcinoma. This study investigated the clinicopathological implications of this polymorphism in oral carcinoma. We found that 79% of oral carcinoma patients had A/A (Ile/Ile) genotype and 21% had A/G (Ile/Val) genotype, with a G (Val) allelic frequency of 0.10. Univariate analysis indicated a significantly higher Val allelic frequency in cases having nodal metastasis or tumor recurrence; and Val allele was associated with poorer recurrence-free survival of patients. Multivariate analysis after adjusting confounding factors by logistic regression analysis indicated that patients carrying Val allele had a 8.79- and 4.25-fold higher risk for nodal metastasis and recurrence, respectively. Using Cox proportional hazard model, the risk of tumor recurrence was 3.35-fold higher in patients carrying Val allele. This is the first report demonstrating that the Val allele of HER-2 codon 655 could be an independent predictor for oral carcinoma progression.