Inactivation of TCF7, a WNT transcriptional mediator, in CD4+ T cells or pharmacological inhibition of ligand-mediated WNT signaling results in increased CD8+ T cell infiltration and reduced pancreatic cancer growth, identifying WNT signaling as a regulator of the pancreatic cancer immune microenvironment. The gene discussed is CD4; the disease is familial pancreatic carcinoma.