检测20例食管、贲门癌患者围术期外周血中天然杀伤细胞（NK细胞）活性水平，发现术前NK细胞活性与正常人相比明显下降，切除肿瘤后第一天即开始大幅回升，且呈逐步上升趋势，2例行探查术患者术后NK细胞活性水平与术前相当，1例术后6个月复发者NK细胞活性水平极度下降。研究结果表明，NK细胞在人体抗肿瘤免疫监视中起重要作用，动态检测外周血中NK细胞活性水平可作为肿瘤的辅助诊断、判断疗效及预后、早期发现癌复发和转移的一个重要指标。 The perioperative peripheral blood natural killer (NK) cell activity was detected in 20 patients with esophageal and cardiac cancer and it was found that the activity of NK cells before surgery was significantly lower than that of normal subjects, and it began to rebound significantly on the first day after tumor removal. The rate of NK cell activity in patients undergoing exploratory surgery was similar to that before surgery. The activity of NK cells in one patient who relapsed 6 months after surgery was extremely decreased. The results show that NK cells play an important role in human anti-tumor immune surveillance. Dynamic detection of NK cell activity in peripheral blood can be used as an auxiliary diagnosis of tumors, judging efficacy and prognosis, and early detection of cancer recurrence and metastasis as an important indicator.