The present study was designed to examine the immunotherapeutic properties of lymphokine-activated killer (LAK) cells against uterine endometrial cancers. Three endometrial cancer cell lines, ISHIKAWA, SNG-M, and HHUA, were shown to be specifically lysed in short-term 51Cr-release assay, although the susceptibility was different among the cell lines. The xenograft tumors of ISHIKAWA and SNG-M exhibited high susceptibility to LAK cells in the in vitro assay and responded well to the adoptive transfer of LAK cells in nude mice. On the other hand, the xenograft of HHUA showed low reactivity to LAK cells and showed no response to the adoptive immunotherapy. However, the adoptive transfer of LAK cells combined with intraperitoneal administration of both recombinant interleukin-2 (rIL-2) and lentinan markedly inhibited the growth of HHUA xenografts in nude mice, while no response was observed in nude mice treated with LAK cells plus either rIL-2 or lentinan, or treated with rIL-2 plus lentinan alone. These results suggest the clinical application of adoptive immunotherapy in association with LAK cells, rIL-2, and lentinan as a treatment of gynecologic cancers.