Tim-3 expression by peripheral natural killer cells and natural killer T cells increases in patients with lung cancer--reduction after surgical resection.

BACKGROUND The purpose of this study was to investigate Tim-3 expression on peripheral CD3-CD56+ natural killer (NK) cells and CD3+CD56+ natural killer T (NKT) cells in lung cancer patients. MATERIALS AND METHODS We analyzed Tim-3+CD3-CD56+ cells, Tim-3+CD3-CD56dim cells, Tim-3+CD3-CD56bright cells, and Tim- 3+CD3+CD56+ cells in fresh peripheral blood from 79 lung cancer cases preoperatively and 53 healthy controls by flow cytometry. Postoperative blood samples were also analyzed from 21 members of the lung cancer patient cohort. RESULTS It was showed that expression of Tim-3 was significantly increased on CD3-CD56+ cells, CD3- CD56dim cells and CD3+CD56+ cells in lung cancer patients as compared to healthy controls (p=0.03, p=0.03 and p=0.04, respectively). When analyzing Tim-3 expression with cancer progression, results revealed more elevated Tim-3 expression in CD3-CD56+ cells, CD3-CD56dim cells and CD3+CD56+ cells in cases with advanced stages (III/IV) than those with stage I and II (p=0.02, p=0.04 and p=0.01, respectively). In addition, Tim-3 expression was significantly reduced on after surgical resection of the primary tumor (p<0.01). CONCLUSIONS Tim-3 expression in natural killer cells from fresh peripheral blood may provide a useful indicator of disease progression of lung cancer. Furthermore, it was indicated that Tim-3 might be as a therapeutic target.