Clinical impact of intratumoral natural killer cell and dendritic cell infiltration in gastric cancer

Intratumoral natural killer cells (NKC) and dendritic cells IDC) may affect the clinical features of various gastrointestinal cancers. However, the re lationship between intratumoral NKC and DC remains unclear. We examined 169 patients with gastric cancer who underwent gastrectomy at Kagoshima Univer sity Hospital. Immunohistochemical staining of CD57 and 5-100-protein was p erformed to evaluate NKC and DC infiltration, respectively. A total of 25 a reas containing pericancerous tissue were selected for determining the numb er of NKC and DC under high power microscopy (x 400). Patients were classif ied into two groups according to NKC and DC population. Intratumoral lympho cytic infiltration was also calculated in 15 areas with a high power ( x 40 0) objective. The degree of NKC and DC infiltration was gradually decreased according to the progression of nodal involvement. Patients with many NKC infiltration had a lower positivity of lymph node metastasis and lymphatic invasion than patients with little NKC infiltration. DC infiltration was al so negatively correlated with depth of invasion. lymph node metastasis and curativity. DC infiltration was positively correlated with lymphocytic infi ltration (P = 0.01. r = 0.6). The 5-year survival rates of patients with ma ny NKC infiltration and patients with DC many infiltration were 75 and 78%. respectively, both of which were significantly better than that of patient s with little NKC and DC infiltration (P < 0.05). NKC may be activated with out DC or intratumoral lymphocytes. Intratumoral NKC may act as an independ ent immunologic effector against tumor cells, unlike DC. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.