Delayed hypersensitivity-induced regression of human neoplasms

Abstract

Delayed hypersensitivity reactions were induced over primary and metastatic tumors of the skin in patients with basal cell carcinoma, mycosis fungoides, lymphoma metastatic to the skin, and carcinoma of the breast metastatic to the skin. Patients were sensitized with 2000 μg dinitrochlorobenzene (DNCB), followed by local application of 100 μg DNCB over tumor and normal skin; 20/21 patients were sensitized to DNCB. In 12/19 patients, the delayed hypersensitivity reaction over tumor tissue was greater than over normal skin. In 13 patients, regression of treated tumor nodules compared to untreated nodules was noted. Not only primary skin cancers but also carcinomas and lymphomas metastatic to the skin regressed. These findings have relevance to the existence of an immunologic surveillance mechanism in the cancer patient.