Three of these receptors, 2B4 (CD244), CS1 (CRACC, CD319) and LLT1 (CLEC2D), were cloned in our laboratory [28,29,30] and have been shown to play a role in other cancers and diseases, such as Systemic Lupus Erythematosus (SLE), prostate cancer and Triple-Negative Breast Cancer (TNBC), as well as other leukemias [31,32,33,34,35,36]. The gene discussed is CLEC2D; the disease is systemic lupus erythematosus.