Neural cell adhesion molecule expression: No correlation with perineural invasion in cutaneous squamous cell carcinoma of the head and neck

Background. Perineural invasion (PNI) in cutaneous squamous cell carcinoma of the head and neck (CSCCHN) is associated with decreased survival, particularly in patients with clinical signs of cranial nerve involvement. There is evidence to indicate that neural cell adhesion molecule (N-CAM) confers capability of PNI. We analyzed our own patient population to determine if N-CAM predicted clinical PNI in CSCCHN. Methods. Tissue from patients with CSCCHN and clinical PNI, who underwent surgery between 1998 and 2005, was immunostained for N-CAM. In addition, non-PNI CSCCHN and normal nerve sections were also stained. A section of neuroendocrine tumor was included in each slide as a positive control. In addition, most of the sections also had an "inbuilt control" in the CD56 positive natural killer T cells that formed part of the inflammatory reaction to the tumors. Results. Tissue was available from 14 patients with CSCCHN and clinical PNI. The analysis was carried out in 14 patients without PNI and 4 normal nerves. N-CAM was not expressed in any of our PNI CSCCHN specimens or non-PNI controls. It was strongly expressed in the neuroendocrine tumors and positive in-built controls, as well as in normal nerve tissue. Conclusion. N-CAM expression did not predict neurotropism in our patient population. Additional studies are required to identify the cell surface markers expressed by CSCCHN which confer neurotropism capabilities.