Antitumour effect of intratumoral injection of human recombinant interleukin-2 in patients with hepatocellular carcinoma: a preliminary report.

Five hepatoma patients with small resectable tumour received an intratumoral injection of recombinant interleukin-2 (rIL-2) once weekly over 2-4 weeks (1.05 x 10(6)-3.6 x 10(6) U in total per patient). Tumour regressions of 32% and 57% were observed in two patients at day 42 after the first rIL-2 injection. No response was observed in two patients and disease progressed in one. Lymphokine-activated killer (LAK) activity was enhanced and Leu-11+ cells increased in the peripheral blood in the patients with 32% and 57% tumour regression after rIL-2 therapy. However, LAK activity, Leu-7+ cells were reduced in the patient who progressed. No consistent changes in Leu-2a+ cells and Leu-3a+ cells were demonstrated. In the three patients showing no response or 32% tumour regression, hepatic segments containing tumour were resected; histologically the tumour showed severe necrosis and lymphocytic infiltration in the patient with 32% tumour regression but mild or moderate changes in the other two. IL-2 mediated tumour killing can be induced in tumours by intratumoral injection of rIL-2, leading to tumour regression.