CD28 (Cluster of Differentiation 28) is a homodimeric stimulatory cell surface receptor of the immunoglobulin (Ig) superfamily that is located on the chromosome 2q33.2. It is expressed on naive T cells and has also been found on the surface of plasma cells, eosinophils, and neutrophils. CD28 remains the most extensively studied costimulatory molecular and is a primary one for T-cell activatio. The control of T-cell responses through CD28 co-stimulation provides a means of anti-self and antimicrobial immunity. CD28 is essential for the lymphocyte activation and survival. A number of antigen-experienced T-cells lose CD28, and then can be re-activated without its engagement. Diseases linked to CD28 involve mycosis fungoides and Sezary's disease and the related pathways are Th2 differentiation pathway and RET signaling. MUC1 (Mucin 1, cell surface associated), also referred to tumor-associated epithelial membrane antigen, EMA, MCD or CD227, is a 122 kDa single-pass type I transmembrane protein mapping at the chromosome 1q22. It is generally expressed on glandular or luminal epithelial cells of the mammary gland, stomach, esophagus, duodenum, pancreas, prostate, uterus, and lungs, and lesser in hematopoietic cells, but absent in the skin epithelium and mesenchymal cells. MUC1 gene coding for a membrane-bound protein, a member of the mucin family, is an O-glycosylated protein that functions in forming protective mucous barriers on epithelial cell surfaces. And they also play a part in intracellular signaling. Abnormally glycosylated MUC1 is overexpressed in most human epithelial cancer cells and has been regarded as an oncogenic molecule.