Bladder Tumer Associated Antigen

BLADDER TUMOR ASSOCIATED ANTIGEN
The bladder tumor associated antigen detected by the BTA stat^® Test and the BTA TRAK^® Assay has been identified as complement factor H related protein (CFHrp), a variant of human complement factor H (FH). FH plays an important role in regulating the complement system.
The Complement System
	The complement system is part of the normal immune response that protects the body from infection by bacterial cells or viruses. For example, once bacteria are recognized as foreign by the immune system, a complex series of events is put in motion leading ultimately to the formation of the membrane attack complex (MAC). The MAC functions to destroy the invader by poking holes in the cell membrane.
Human Complement Factor H
	FH is a soluble protein that protects normal cells from being destroyed by the complement system. Recent research has shown that many cancer cell lines, including bladder cancer, make variant FH molecules (CFHrp) presumably to protect themselves from being destroyed by the complement system. Production of this type of protein by the tumor may keep it from being destroyed even though the immune system recognizes it as foreign.
Bladder Tumor Associated Antigen
	The bladder tumor associated antigen has been shown to be produced by bladder tumor cells in cell culture and shed into the urine of bladder cancer patients where it can be detected using the BTA stat Test and/or BTA TRAK Assay. It has also been shown to be produced by bladder tumor cells using in situ hybridization. In addition, cultured cells, inlcuding bladder cancer cells, have been shown to be significantly more susceptible to lysis by complement in the presence of monoclonal antibodies specific for FH/CFHrp.