TJP1 and neoplasm: The MMTV-PyVT/HdhQ111/Q111 tumours had lower levels of the tight junction protein zonula occludens 1 (ZO1), E-cadherin and β-catenin, and an increased level of the mesenchymal marker vimentin compared to MMTV-PyVT/HdhQ7/Q7 tumours.