In addition, myelocytomatosis viral oncogene homolog (MYC) amplification, Notch pathway activation, Achaete-scute homolog-1 (AscL1) gene expression, PIK3CA mutations, and catalytic polypeptide hypermutation by apolipoprotein B (ApoB) mRNA editing enzyme have been implicated in SCLC transformation (11, 17–20). This evidence concerns the gene PIK3CA and small cell lung carcinoma.