HLA-S and small cell lung carcinoma: The specific molecular subtypes of SCLC have been further characterized by association with expression of neuroendocrine markers and limited expression of immune-associated genes and/or an antigen-presenting and processing machinery (APM) signature in the immune-cold SCLC-A and SCLC-N subtypes, in contrast to the elevated expression of immune checkpoint molecules and human leukocyte antigens (HLAs) seen in the immunologically inflamed SCLC-I subtype [1, 24].