The importance of endogenous Gal-1 in tumor-promotion is substantiated with results obtained using Gal-1 knockout mice; while injection of tumor cells alone or in combination with MSCGal-1−/− results in highly delayed tumor appearance in Gal-1 knockout animals, co-transplantation of wtMSCs by-passes the absence of endogenous Gal-1. This evidence concerns the gene LGALS1 and neoplasm.