CTSK and cancer: On the other hand, AKR1B1 (SMD = 0.3; 95% CI 0.01; 0.60; P < 0.01), CTSK (SMD = 1.52; 95% CI 0.98; 2.06; P < 0.01), MMP2 (SMD = 1.02; 95% CI 0.51; 1.53; P < 0.01), TLR4 (SMD = 0.85; 95% CI 0.34; 1.37; P < 0.01) were up-regulate in cancer groups, which might be the tumor proto-oncogene.