Figure 3. Reduction of tumor burden, by operation or chemotherapy, led to the obvious decline of TREM-2 expression.

Blood samples were collected from 20 patients with lung cancer before and after chemotherapy (at the beginning of cycle 3) in the department of respiratory medicine (7 patients were squamous cell carcinomas and 13 patients were adenocarcinomas), and 15 patients with lung cancer before and after operation (after one month) in the department of thoracic surgery (5 patients were squamous cell carcinomas and 10 patients were adenocarcinomas). The patients who received chemotherapy were divided into two group according to the therapeutic response: Group1 was including the patients with SD and PD (n=10) while Group2 included the patients with PR (n=10). The last two columns contained the patients with lung cancer before and after the operation. The expression of TREM-2 on monocytes detected by FACS was down-regulated dramatically in patients with PR after chemotherapy and in those who received surgical resection while it was unchanged or even elevated in patients with SD and PD. *p < 0.05 compared with that before chemotherapy; # p < 0.05 compared with that before operation.