Tumor deposition of laminin-5 and the relationship with perineural invasion

Perineural invasion (PNI) is increasingly being recognized as an important indicator of aggressiveness in head and neck squamous cell carcinoma. The mechanisms of PNI are poorly understood. Laminin-5, an important basement membrane constituent, has been shown to be essential in head and neck squamous cell carcinoma invasion and motility. We hypothesized that tumors exhibiting increased expression of laminin-5 are more likely to be neurotropic.

Analysis of archived surgical specimens with and without PNI for presence and intensity of laminin-5 tumor staining.

Immunohistochemistry of archived head and neck squamous cell carcinoma specimens with known PNI was performed with anti-laminin-5 antibodies and appropriate positive and negative control specimens. The staining patterns were characterized as follows: A, few to no tumor cells positive; B, some peripheral cells positive; C, all peripheral cells positive; and D, almost all tumor cells positive. Statistical analysis was by chi2 analysis.

Forty-six PNI-positive and 18 PNI-negative specimens were analyzed. The staining distribution for the PNI-positive specimens was as follows: 2% for A, 41% for B, 46% for C, and 11% for D. For tumors without PNI, the distribution was 28% for A, 50% for B, 22% for C, and 0% for D (P = .005). In PNI-positive tumors, no significant difference in staining was seen between areas with and without PNI.

We found a significant correlation between laminin-5 staining and the presence of PNI in head and neck squamous cell carcinoma. Expression of laminin-5 by tumors is, possibly, an important step in the process of PNI. These preliminary findings support the concept that deposition of basement membrane constituents are required in the multistep process of nerve invasion.