All of the following are tumour markers, EXCEPT:

Examples of tumor markers are alpha fetoprotein, carcinoembryonic antigen, human chorionic gonadotropin, lactate dehydrogenase and neuron specific enolase. Tumor markers: They are biologic markers usually proteins associated with malignancy. It may be produced by a tumor itself as a by product of malignant transformation or by the body in response to the tumor. It may be used to identify a paicular disease in which case it may be used for diagnosis, staging or population screening. It can also be used to detect presence of occult metastatic disease, to monitor response to treatment or to detect recurrent disease. Ref: The Surgery of Childhood Tumors edited by Robe Carachi, chapter 4.