CLDN3 and cancer: In addition, factors previously identified to be specific markers of lung adenocarcinoma were upregulated, including PROM2, CLDN3, and TJP3, as were genes proposed to have potential diagnostic or prognostic value in human cancers, including MMP9, AGR2, SULF1, NHSL1, LGR5, MUC1, and PIK3C2G.