CDH2 and small cell lung carcinoma: The dysregulated expression of BMP1, BMP7, CALD1, KRT14, CAV2, IL1RN, and adherent junctions proteins (CDH1, CDH2, DSC2), promotes the primordial detachment between the distal cancer cells, depriving the central cancer cells of the blood supply leading to comedonecrosis in AC and LCNEC and “geographic” in SCLC.