Human papillomavirus genotypes and p16 expression in oral leukoplakia and squamous cell carcinoma

Several studies have shown a broad variation in the prevalence of human papillomavirus (HPV) in oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC), whereas the relationship is less well-defined and specific HPV genotypes lack examination in OLK. In the present study, the role of HPV and surrogate p16 expression was investigated to explore the correlation and pathogenesis in OLK and OSCC. Polymerase chain reaction (PCR) and flow-through hybridization technology were utilized to detect HPV genotypes in oral exfoliated cells from 30 healthy volunteers, 103 OLK and 30 OSCC patients. Expression of p16 was assessed by immunohistochemistry (IHC) in biopsies from these OLK and OSCC, in addition to 15 normal oral mucosal tissues as the control group. The healthy controls showed 3.3% (1/30) HPV presence; In OLK and OSCC, the detection rate was 4.9% (5/103), 3.3% (1/30), respectively. No significant relationship between HPV and OLK or OSCC was observed when compared with the control group (P>0.05). All 6 HPV-positive OLK and OSCC cases had p16 overexpression. But the sensitivity of p16 IHC was poor, because 88.4% (38/43) of p16 over-expressed OLK were HPV negative. There was no statistical significance between HPV and the sex, age, site, alcohol consumption, or smoking. These findings suggested HPV had a low prevalence in OLK and OSCC. This suggests the detection of HPV genotypes by PCR in exfoliated cells combined with p16 IHC may be more accurate to represent HPV infection.