LGALS9 and primary cutaneous T-cell non-Hodgkin lymphoma: In CTCL research, these mice, together with the EL4 mouse T-cell lymphoma model, have aided in discovering that the expression of galectin-9 on tumor cells is inversely proportional to CD8+ T cell infiltration in the skins of EL4 mouse model and serum levels of galectin-9 correlate with disease severity.