Furthermore, considering the crucial role of immune checkpoint genes in the negative regulation of tumor immunity (PD1, PD-L1, CTLA4, IDO1, TIGIT, TIM-3, and LAG3), we analyzed the expression of these genes and found that except for PD1, all other immune checkpoint genes were upregulated in ER cluster B (Figure 3E). Here, HAVCR2 is linked to neoplasm.