TP53, retinoblastoma 1 (RB1), suppressor of mothers against decapentaplegic 4 (SMAD4), Harvey rat sarcoma viral oncogene homolog (HRAS), adenomatous polyposis coli (APC), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and G protein subunit alpha Q (GNAQ) were among the genes with recurrent somatic alterations in SDC, and the myeloblastosis proto-oncogene-NHS-like 1 (MYB-NHSL1) fusion gene was also noted, which can aid in further differentiating SDC from adenosquamous carcinoma and LCUD [17,18]. This evidence concerns the gene SMAD4 and adenosquamous carcinoma.