CLDN9 and metastasis: We additionally examined the link between CLDN family gene mRNA levels and CRC patient lymph node metastasis, revealing a significant relationship between the expression of CLDN1, CLDN2, CLDN3, CLDN7, CLDN8, CLDN9, CLDN11, CLDN14, CLDN16 and CLDN23 nodal metastasis in COAD and READ (Figures 4A, B, C, G, H, I, K, M, N, R) (Figures 5A, B, C, E, F, G, I, K, M, O).