Inhibition of leukocyte migration by soluble tumor extracts in human malignant melanoma

Leukocytes from 63 melanoma patients and from 38 control donors were examined by a leukocyte migration inhibition (LMI) assay. The antigens were three soluble extracts of fresh melanomas and one of lung cancer. A total of 62 out of the 99 (62.6%) blood samples from melanoma patients reacted with allogeneic extracts of melanoma in comparison with 11 out of the 48 (22.9%) in the controls (the values significantly different; P less than 0.001). The migration inhibition of melanoma patients' leukocytes by the lung cancer extract was markedly less than inhibition by any of the melanoma extracts. LMI in patients with distant metastases before treatment (9 out of the 11--81.8% positive results) was higher than in patients with regional lymph node metastases (5 out of the 9--55.5%) and than in patients with localized disease (3 out of the 7--47.8%). The reactivity of patients after surgery was higher than in patients before surgical resection of the tumor. Positive reactions were less frequent in patients with distant metastases receiving chemotherapy or/and immunotherapy than in patients before treatment.