To exclude the possibility that tumor rejection in STAT3−/− mice was due to off-target effects of STAT3 deletion on non-hematopoietic tissues, tumor growth studies in lethally irradiated WT mice reconstituted with either STAT3+/+ or STAT3−/− bone marrow cells were performed, and it was found that growth of B16 or MB49 tumors was completely blocked in mice reconstituted with STAT3−/− bone marrow cells. This evidence concerns the gene STAT3 and neoplasm.