In contrast with NSCLC, PD-L1 expression in PSCGCC is related to the presence of adenocarcinoma markers such as TTF-1 and/or Napsin A. Another hope for patients with lung SC is the relatively higher frequency in this subtype of exon 14 skipping of MET (hepatocyte growth factor receptor gene) [20]. This evidence concerns the gene TTF1 and non-small cell lung carcinoma.