Effects of tobacco abuse on major chromosomal instability in human papilloma virus 16-positive oropharyngeal squamous cell carcinoma

A substantial number of patients with oropharyngeal squamous cell carcinoma (OPSCC) have two oncogenic risk factors: Human papilloma virus (HPV) infection and tobacco use. These factors can be competitive or synergistic at the chromosomal and genomic levels, with strong prognostic and therapeutic implications. HPV16 has been shown in vitro to be a high-risk HPV that induces low rates of chromosomal copy number alterations. However, chromosomal instability can be increased by smoking. Evaluating chromosomal instability in HPV-positive patients according to their smoking status is therefore critical for assessing the prognosis and therapeutic impact. The aim of this study was to assess chromosomal instability in patients with HPV-positive OPSCC according to smoking status. Chromosomal instability was investigated with array-based comparative genomic hybridization (aCGH) in 50 patients with OPSCC. Differences in chromosomal alterations were examined according to the HPV and smoking status of the patients. HPV-positive tumors (24/26 were HPV16-positive) had fewer genomic aberrations (P=0.0082) and fewer breakpoints (P=0.048) than HPV-negative tumors. We confirmed the association between HPV-positive OPSCC and chromosomal losses at 11q. We verified the association between HPV-negative OPSCC and losses at 3p and 9p and gains at 7q and 11q13. In the patients with OPSCC who were HPV-positive, the total number of chromosomal aberrations per tumor was significantly higher in the group of patients who were smokers (P=0.003). However, the cytobands did not differ significantly according to the smoking status. On the whole, the data of this study may help to improve the stratification of HPV-positive OPSCC patients and must be supplemented by next-generation sequencing studies in order to describe the mutational and transcriptomic profiles of such patients according to smoking status.