Cancer/testis antigen 1 also known as LAGE2 or LAGE2B is a protein that in humans is encoded by the CTAG1B gene. It is most often referenced by its alias NY-ESO-1. Cancer/Testis Antigen 1B is a protein belonging to the family of Cancer Testis Antigens (CTA) that are expressed in a variety of malignant tumours at the mRNA and protein levels, but also restricted to testicular germ cells in normal adult tissues. A clone of CTAG gene was originally identified by immunological methods in oesophageal carcinoma using patient serum.[6] The aberrant re-expression of CTAs is induced by molecular mechanisms including DNA demethylation, histone post-translational modification, and microRNA-mediated regulation. The effect of DNA demethylation is evident by the capability of demethylating agents, such as 5-aza-2-deoxycytidine, to induce CTAs re-expression in tumour cells but not in normal epithelial cells.