The CUB and Sushi multiple domains 1 (CSMD1) is a tumor suppressor gene reported to be associated with poor prognosis in many cancer types including breast cancer, gastric cancer, head and neck squamous cell carcinoma (HNSCC), and hepatocellular carcinoma (Deng et al., 2012; Zhang et al., 2019; Jung et al., 2018). The gene discussed is CSMD1; the disease is breast cancer.