Epidermoid carcinoma-cell culture supernatant's inhibition of monocyte chemotaxis: evidence for a tumour-mediated effect.

Epidermoid carcinoma-cell culture supernatants obtained from three laryngeal-epidermoid carcinoma patients were tested in the monocyte suspensions of 13 stage I and stage II (TNM) head and neck epidermoid-carcinoma patients and seven healthy controls for its chemotactic inhibitor activity in vitro with a modified Boyden chamber method. Using 2% casein as the chemoattractant, mean values of monocyte chemotaxis and random migration were found to be decreased in the patient group compared to the controls in a simultaneous assay recorded by the "leading front" method. Simultaneous experiments performed with the supernatant revealed a nearly double-fold increase in random migration and depressed chemotaxis in both groups. The supernatant caused a further depression in the chemotaxis of the patients' already-disabled monocytes, which is thought to be representative for advanced stage tumours. The depression of monocyte chemotaxis, especially in the control group, implies the presence of tumour-derived chemotactic inhibitor(s) for monocytes in the supernatant.