To explore the possible immune-regulatory role of SUV39H2 in different cancer types, we analyzed the relationship between SUV39H2 expression, immune cell infiltration, and immune checkpoint molecule expression in HNSCC, LIHC (Liver Hepatocellular Carcinoma), BRCA (Breast Invasive Carcinoma), and PAAD (Pancreatic Adenocarcinoma) tumors based on data from the TCGA database. The gene discussed is SUV39H2; the disease is invasive breast carcinoma.