CTLA4 and small cell lung carcinoma: Key findings include a high expression of markers like EpCAM, TTF-1, Ki67, cytokeratin, and HER, as well as differences between NSCLC and SCLC in antigens such as MUC-1, CD56, HLA-DR, CD39, CD184, PD-L1, PD-L2, and CTLA-4.