Augmentation of Natural Killer Activity after Peritumoral Administration of OK-4 32 In Rectal Cancers

Abstract

OK-432 was administered preoperatively into the peritumoral tissues of 23 patients with rectal cancer. Natural iller (NK) activity of lymphocytes was isolated from peripheral blood, portal vein blood, and tumorous lesions, andthe regional lymph nodes were measured by⁵¹Cr release assay. There was no effect on peripheral bloodlymphocytes (PBL) or lymph node lymphocytes (LNL) with the administration of OK432. NK activity of tumorinf iltrated lymphocytes (TIL) was increased in half the cases after the administration of OK-432. NK activity of portal vein blood lymphocytes (PVL) was higher than that of PBL following OK-432 administration. The cases which showed high NK activity on TIL also showed high activity on PVL. The above results suggested that peritumoral administration caused increases in both TIL and PVL activity. Therefore, the preoperative injection of OK-432 to the peritumoral region in rectal cancer patient could be effective as preoperative adjuvant therapy, particularly for the inhibition of liver metastasis.