Perineural invasion in oral squamous cell carcinoma: incidence, clinical impact and molecular insight

Background Perineural invasion (PNI) has been associated with poor prognosis in oral squamous cell carcinoma (OSCC). Nerve growth factor (NGF) and its receptor tyrosine kinase A (TrkA) may play a role in PNI in OSCC. Objective To characterize the incidence and prognostic correlation of PNI in OSCC and to determine whether NGF and TrkA expressions could be used as biological markers for PNI in OSCC. Methods A retrospective review of pathology reports of 430 patients with OSCC treated from 1992 to 2014 in Tayside, Scotland, and followed for 5 years or until death was undertaken. The expression of NGF and TrkA was assessed with immunohistochemistry in 132 tissue sections of OSCC. Results PNI was identified in 17.4% of OSCC. High expression of NGF and TrkA was seen in 84% and 92% of OSCC, respectively. PNI-positive OSCC expressed NGF and TrkA with greater frequency than PNI-negative OSCC (P 4 mm (P Conclusions Higher level of expression of NGF and TrkA many predict PNI and therefore may be considered as biological markers for PNI in OSCC. Pain could be a predictive for PNI and NGF overexpression. PNI and NGF expression can predict the aggressiveness and prognosis of OSCC.