By comparing the sensitivity of SHOX2 and RASSF1A, we found that in patients with LUAC, LUSC, LCNC, SC, and undefined, the sensitivity of SHOX2 methylation detection was significantly higher than that of RASSF1A (P = 0.012), and in patients with SCLC, the sensitivity of RASSF1A methylation was higher (88.1% vs. 79.3%). Here, SHOX2 is linked to small cell lung carcinoma.