Purpose To evaluate the impact of HPV16 load (VL-the
number of virus genome copies per cell) and P16 expression
on prognosis of patients with squamous cell carcinomas
(SCCs) of head and neck (HN).
Materials and methods HPV16 presence was assessed in
the group of 109 patients with HNSCCs by quantitative polymerase
chain reaction (qPCR). VL (assessed by qPCR) and
P16 expression (evaluated by immunohistochemistry) were
analysed only in the subgroup of HPV16-positive tumours.
These features were correlated with 5-year overall survival
(OS) and disease-free survival (DFS).
Results HPV16 infection was found in 36 tumours
(33.0%). Virus-positive patients had better OS and DFS
than those without infection (P = 0.041 and 0.005). Among
HPV16-positive HNSCCs, 18 (50.0%) had higher VL
(median value > 6764.3 copies/cell) and 25 (73.5%) P16 over expression. The significant differences in OS and
DFS (P = 0.008 and 0.004) were noticed according to VL,
wherein 100% DFS was found for patients with higher
VL. According to P16 expression, significant difference
was found only for OS (P = 0.020). In multivariate analysis,
VL (P = 0.045; HR = 2.795; CI 0.121-1.060) and the
level of smoking (P = 0.023, HR = 2.253; CI 1.124-4.514)
were independent factors affecting DFS of HPV16-positive
patients.
Conclusion On the basis of viral load, it is possible to
differentiate prognosis of patients with HPV16-positive
HNSCCs. In this subgroup, viral load has stronger prognostic
potential than P16 expression.