In addition, the results from the other four histological types showed similar performance (LUAC 52.5% vs. 13.3%, LUSC 82.7% vs. 11.1%, SCLC 96.3% vs. 5.9%, and undefined 60.6% vs. 9.1%), indicating that SHOX2 and RASSF1A methylation in BFF/BALF is a genetic biomarker that can be used in almost all histological subtypes of lung cancer. Here, RASSF1 is linked to small cell lung carcinoma.