MMP9 and lung cancer: When we compared the expression of the above mentioned genes between both the cohorts–primary and metastatic we found that CLDN4, MMP9, OPN, CDKN2A, TP53, MUC16 and CD44v6 showed significant up-regulation and VEGFA and TGFBR2 showed significant downregulation in liver metastatic patients as compared to primary lung cancer.