IL21 and neoplasm: To determine whether the reduced carcinogenesis observed in IL-21 KO-Apcmin/+ mice was associated with a reduced activation of STAT3 and/or NF-kB, we compared p-STAT3 Y705 and p-NF-kB/p65 Ser536 expression in non-tumor and tumor tissues derived from colonic extracts of control and IL-21 KO-Apcmin/+ mice killed on day 56.