Tumor-infiltrating lymphocytes and prognosis of hepatocellular carcinoma

Tumor-infiltrating lymphocytes (TIL) were isolated from 17 human hepatocellular carcinomas (HCC). The proliferation of TIL cultured with recombinant interleukin-2 (rIL-2) was evaluated. We also examined prognosis in relation to TIL. Successful expansion of TIL was achieved in 16 of the 17 lesions. In 10 of the 16, TIL increased more than 100-fold. Cytotoxicity to the allogeneic HCC cell line, HC-4, was demonstrated in all 13 TIL cultures tested. Maximum cytotoxicity was noted two to four weeks after culture. No statistical difference was observed either with respect to prognosis based upon growth rate or the cytotoxicity demonstrated in vitro. The initial number of TIL per unit weight of tumor was, however, significantly greater in the group for which the prognosis was good (19.0 +/- 5.1 x 10(6) vs. 5.6 +/- 1.6 x 10(6), P < 0.05). It would appear that greater lymphocytic tumor infiltration is a prognostic marker.