KRT19 and neoplasm: As this incidence was too low to draw any conclusions about the role of α3β1 in the malignant progression of tumors, we selected seven K19 Itga3 KO and seven WT mice with low tumor burden and treated them with TPA for up to an additional 10 wk, until they had to be euthanized because of the tumor burden or ulceration of tumors.