No evidence for an association between natural killer cell activity and prognosis in melanoma patients

Natural killer cell (NK) activity against allogeneic melanoma and Chang liver target cells were measured in a group of 212 patients with primary (stage I) melanoma and 85 patients with metastases in regional lymph nodes (stage II) 2-4 weeks after surgical removal of their tumor. No significant correlation was established between NK activity measured at this time and the recurrence-free period or death from melanoma in prospective studies ranging from 3 to 5 years. Trends for an association between these factors appeared to mainly reflect the influence of tumor growth on NK activity. These studies do not prove that NK activity is not important in host defences against melanoma but do suggest that such measurements in tumor-bearing patients are not related to subsequent prognosis of the patient.