A search for common tumor specific antigen and serum blocking factor in head and neck epidermoid carcinomas.

In vitro, colony inhibition tests using lymphocytes and serum from 42 patients with other carcinomas, and 12 control patients with no carcinoma, were performed using cultured target cells (CALI). Target cell colony counts were significantly diminished by lymphocytes of 2 of 12 (16.7 percent) patients with no cancer, compared with those 26 of 42 (61.9 percent) patients with epidermoid carcinoma. An unexpected finding was significant colony inhibition of lymphocytes of 23 of 27 (85.2 percent) patients tested within 24 months of diagnosis of carcinoma compared with significant inhibition in only 3 of 15 (20 percent) patients tested after 24 months of diagnosis of carcinoma. Serum blocking factor was found in 9 of 42 (21.4 percent) patients with epidermoid carcinoma. It was found on follow-up that four of these nine (44.4 percent) had later recurrent or new tumors compared to recurrence or new tumor incidence of only 6 of 33 (18.2 percent) patients with no serum blocking factor present in the serum.