Figure 2. The level of TREM-2 on pulmonary MΦs positively correlated with pathological staging and lymph nodes metastasis of lung cancer.

A. Adjacent lung tissues sections from each group were stained with TREM-2 and F4/80, respectively. Representative photomicrographs were shown (Arrows in A showed TREM-2⁺ MΦs). B. The intensity of staining of TREM-2 was quantified using mean integrated optical density (IOD) (mean IOD = sum IOD/sum area). C. The degree of lymph nodes metastasis was according to 7th TNM classification. The results represent the mean ± SEM. n: controls, 21; stage I, 15; stage II, 15; stage III, 15; stage IV, 11; **p < 0.01 compared with the previous group. DM: distant metastasis.