Neural Cell Adhesion Molecule in Adenoid Cystic Carcinoma Invading the Skull Base

Abstract

Neural cell adhesion molecules (N-CAMs) are expressed in neuromuscular tissues, neuroblastoma, and small cell lung carcinoma. Adenoid cystic carcinoma may invade the skull by either direct extension or neural involvement, particularly along the second and third divisions of the trigeminal nerve (V2 and V3). Eighteen patients with adenoid cystic carcinoma that invaded the skull base were studied. The tumors were graded into predominantly solid (3), cribriform (11), or tubular-trabecular (4) patterns, and neural involvement was evaluated histologically. Paraffin sections were examined by use of monoclonal antibodies for N-CAM and Ki-67, a proliferation marker, with the avidin-biotin-peroxidase method. Fifteen (83%) tumors showed perineural involvement; in the remaining three cases no nerves were present for histologic examination. Fourteen (93%) of 15 tumors with perineural involvement were reactive with N-CAM. Proliferation, measured by the presence of nuclear Ki-67, was markedly increased in tumors with predominantly solid patterns. We demonstrated that N-CAM is expressed in adenoid cystic carcinoma. The role of N-CAM as a neurodeterminant that facilitates the spread of adenoid cystic carcinoma along nerves, however, remains unanswered and warrants further study.