Furthermore, 12 genes (BMP1, BMP7, CALD1, CDH1, COL3A1, COL5A2, EGFR, ERBB3, PLEK2, SNAI2, STEAP1, and TCF4) were differentially expressed among histological subtypes and were all overexpressed in SCLC and LCNEC when compared to TC and AC. Here, COL5A2 is linked to small cell lung carcinoma.