CD40 expression has been previously reported in B-cell malignancies, as well as in a variety of solid tumors including bladder cancer, breast cancer, cervical cancer, colon cancer, gastric cancer, head and neck cancer, lung cancer, melanoma, osteosarcoma, ovarian cancer, pancreatic cancer, and renal cell carcinoma [9–11, 14–22]. This evidence concerns the gene CD40 and breast cancer.