Analysis of HRAS mutations in Japanese patients with oral squamous cell carcinoma

Abstract

ObjectivesThe incidence of oral squamous cell carcinoma (OSCC) is associated with chewing tobacco and heavy consumption of alcohol. OSCC is also associated with Harvey rat sarcoma viral proto-oncogene homolog (HRAS) gene mutations, which are known to be high-risk factors for poor survival outcomes in patients with OSCC. In this study, we analysed HRAS mutations in Japanese patients with OSCC. MethodsTumours and oral mucosal tissue samples were collected from 84 treatment-naïve patients with OSCC, between April 2010 and November 2012 in the Department of Oral and Maxillofacial Surgery at a university hospital in Japan. ResultsAn HRAS mutation was identified in one of the 84 tumours (1.2%) using standard Sanger sequencing. This mutation occurred in codon 13 (c.38G > T) of exon 2, and it corresponded to amino acid substitution p.Gly13Val. Statistical analysis demonstrated that HRAS mutations were associated with chewing tobacco (p < 0.05). Consistent with the fact that Japanese people generally do not chew tobacco, the frequency of HRAS mutations among Japanese patients with OSCC was low. ConclusionEven though HRAS mutations are associated with OSCC, the HRAS gene may be a poor biomarker for investigating OSCC among the Japanese population due to the low frequency of the mutation. This phenomenon may be explained by a relatively low rate of chewing tobacco consumption in this population.