In the presented work, the selected markers for evaluation using multiparametric flow cytometry are of significant importance in cancer biology: epithelial cell adhesion molecule (EpCAM), Mucin-1 (MUC-1), thyroid transcription factor-1 (TTF-1), human epidermal growth factor receptor 2 (HER-2), cytokeratin, Ki67, CD56, CD90, CD38, HLA-DR, CD39, CD73, CD184, programmed death-ligand 1 (PD-L1), programmed death-ligand 2 (PD-L2), and cytotoxic T cell antigen 4 (CTLA-4). The gene discussed is CTLA4; the disease is cancer.