In adoptive immunotherapy of cancer using lymphokine-activated killer(LAK) cells indueed from patients own peripheral blood, the efficient cytotoxicity of LAK cells is a principal requirement. Peripheral blood lyrnphocytes were obtained from 15 patients with cervical cancer and 13 normal as a control, and LAK cells were induced with r-interleukin-2(rlL-2). Cytotoxic activity of cultured cells were measured by a 4h-51 Cr release assay using NK(natural killer)-sensitive K-562 cell line and NK-resistant RAJI target cells, and their surface phenotypes were deterrnined by an imrnunofluorescence significantly increased compared with those activity without rIL-2. Despite the ratio between effector and target cells, the cytotoxic potential of NK and LAK cells of normal wornen were significantly higher than those of cervical cancer patients. (FO) However, LAK ce11 activity was relatively low but increased significantly in patients with cervical cancer. NK cell and LAK cell cytotoxicity in the group of tumor mass, 4 cm were significantly decreased compared with those in the group of tumor mass 4 cm. (Kffector: target ratio = 50:1, NK: P=0.038, LAK : P = 0. 033) Surface phenotypes of peripheral lymphocytes and LAK cells were examined with indirect immunofluorescence method, The CD 3 subpopulations which are known to be major components af LAK cells were not diminished. After LAK cell induction with IL-2, the percentages of CD l6(Natural killer cell) populations were significantly increased in normal(11.2% vs 48.3%) and cervical cancer patients(11.8% vs 47.8 %). These data suggest that 1) the decline of NK and LAK cell act.ivity in cervical cancer patients, 2) the ecreasing cytotoxicity with the increasing turnor mass, 3) the percentage of natural killer cell subpopulation dramatically increased with surfaee phenotype of LAK cells, 4) LAK cells may be applied for passive adoptive immunotherapy.