NEURAL CELL-ADHESION MOLECULE IN ADENOID CYSTIC CARCINOMA INVADING THE SKULL BASE

Neural cell adhesion molecules (N-CAMs) are expressed in neuromuscular tissues, neurobtastoma, and small cell lung carcinoma. Adenoid cystic carcinoma may invade the skull by either direct extension or neural i nvolvement, particularly along the second and third divisions of the t rigeminal nerve (V2 and V3). Eighteen patients with adenoid cystic car cinoma that invaded the skull base were studied. The tumors were grade d into predominantly solid (3), cribriform (11), or tubular-trabecular (4) patterns, and neural involvement was evaluated histologically. Pa raffin sections were examined by use of monoclonal antibodies for N-CA M and Ki-67, a proliferation marker, with the avidin-biotin-peroxidase method. Fifteen (83%) tumors showed perineural involvement; in the re maining 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. W e demonstrated that N-CAM is expressed in adenoid cystic carcinoma. Th e role of N-CAM as a neurodeterminant that facilitates the spread of a denoid cystic carcinoma along nerves, however, remains unanswered and warrants further study.