HAVCR2 and breast cancer: Tim-3 is not only expressed on immune cells but also overexpressed in multiple types of malignant tumors, such as lung cancer (42), gastric cancer (43), colon cancer (44), hepatocellular carcinoma (45), renal cell carcinoma (46), bladder urothelial carcinoma (47), cervical cancer (48), and breast cancer (20, 21, 49).