To test whether galectin-1 signaling contributes to the pathobiology of myelofibrosis in vivo, we tested the impact of a neutralizing anti-galectin-1 monoclonal antibody (Gal-1-mAb3) that binds to a specific sequence in galectin-1 not present in other galectin family proteins (36) in the MPLW515L mouse model. This evidence concerns the gene LGALS1 and myelofibrosis.