He Y, Jia K, Dziadziuszko R, et al. - Since lung cancer shows the highest incidence and fatality among all cancers, researchers evaluated galectin-9 expression on non-small cell lung cancer (NSCLC) tumor cells and tumor infiltrating lymphocytes (TILs). They obtained 136 NSCLC primary tumor samples and performed immunohistochemistry to examine the expression level of galectin-9 protein. These surgical resected samples were obtained from the Medical University of Gdansk, Poland. They found that both NSCLC tumor cells and TILs had galectin-9 expressed on them. In all NSCLC pathological type, the presence of galectin-9 expression was revealed. The correlation of galectin-9 level on TILs with T cell immunoglobulin and mucin-domain containing-3 (TIM-3), programmed cell death protein-1 and programmed cell death-ligand 1 level was evident. In addition, the correlation of galectin-9 level with TIM-3 level was seen on tumor cells. The likelihood of experiencing a poor prognosis was more in patients with low galectin-9 level on tumor cells or high galectin-9 level on TILs.