beta-2-microglobulin in benign and malignant adnexal skin tumors and metastasizing basocellular carcinomas

Immunostaining for beta-2-microglobulin (beta-2m) was performed on various benign and malignant adnexal skin tumors and 3 cases of metastasizing basocellular carcinomas. All the tumors and their metastases, with the exception of 2 basocellular carcinomas gave evidence of beta-2m. Most tumors contained both stained and unstained cells. The stained cells showed differentiation, the unstained ones appeared to be undifferentiated and basal-like in character. The staining of cutaneous tumors for beta-2m may offer a tool for investigating tumor differentiation, but seems not to be of much value in distinguishing malignant from benign lesions.