Natural killer cells in the host response to melanoma

Using an immunoperoxidase technique, we have investigated natural killer (NK) cells in the host response to malignant melanomas and melanocytic nevi in frozen sections. Eight primary melanomas, 12 metastatic melanomas, and 31 dysplastic nevi were studied. NK cells were identified phenotypically using an antibody, B73.1, against an Fc receptor present only on NK cells and neutrophils. Rare NK cells were identified in three of 31 dysplastic nevi and in one of eight melanomas. In contrast, significant numbers of NK cells were identified in ten of 12 metastases.