TREM2 and neoplasm: In 2016, Yao et al. elucidated that, compared with normal control, TREM2 was dramatically overexpressed on peripheral blood monocytes and TAMs of patients with lung cancer and tumor-bearing mice, and there was a positive correlation between the level of TREM2 on pulmonary macrophages and the pathological staging or lymph nodes metastasis of lung cancer, the reduction of tumor burden by surgery or chemotherapy induced the remarkable decrease of TREM2 on the peripheral blood monocytes of lung cancer patients (77).