PLLP and small cell lung carcinoma: The IVW results showed that PSAT1 and PSRC1 all had significant positive correlation with SCLC, PSAT1 [P=0.007, OR=1.156, 95% confidence interval (CI): 1.041-1.283], PSRC1 (P=0.031, OR=1.131, 95% CI: 1.011-1.264); whereas COLEC12, PLLP, and HP all had significant negative correlation with SCLC, COLEC12 (P=0.005, OR=0.798, 95% CI: 0.682-0.933), PLLP (P=0.008, OR=0.606, 95% CI: 0.420-0.875), HP (P=0.011, OR=0.885, 95% CI: 0.805-0.972), as shown in Figure 5.