[10] Galectin-9 also has important cytoplasmic, intracellular functions and controls AMPK[11][12] in response to lysosomal damage that can occur upon exposure to endogenous and exogenous membrane damaging agents such as crystalline silica, cholesterol crystals, microbial toxins, proteopathic aggregates such as tau fibrils and amyloids, and signaling pathways inducing lysosomal permeabilization such as those initiated by TRAIL.

[20] HAVCR2/ galectin-9 interaction attenuated T-cell expansion and effectors function in tumor microenvironment and chronic infections.

[22] The correlative studies analyzing the expression of galectin-9 and malignant clinical features showed controversial results.

[20] Therefore many factors such as tumor type, stage, and the involvement of different galectins should be take into consideration when correlating the expression level and the malignancy.

Galectin-9, through its cytoplasmic action in control of AMPK,[11][12] may affect various health conditions impacted by AMPK, including metabolism, obesity, diabetes, cancer, immune responses, and may be a part of the mechanism of action of the widely-prescribed anti-diabetes drug metformin.