Compound - Diagnostic Marker For Biliary Tract Cancer, Method For Detecting Enzymatic Activity, Method For Diagnosis Of Biliary Tract Cancer, Kit Comprising The Compound, Uses Of The Compound And Method For The Treatment Of Biliary Tract Cancer

A compound having formula 1:

• wherein X1 comprises or consists of molecule C1 and X2 comprises or consists of molecule C2,
• wherein the pair of molecules C1 and C2 is a pair of a fluorescence donor and a fluorescence acceptor,
• and wherein the compound undergoes enzymatic cleavage into the fragments X1-Glu-Arg-Arg-Ala-OH (fragment 1) and X2 (fragment 2) with a generation of a measurable optical signal upon spatial separation of molecules C1 and C2.

An in vitro method for diagnosis of biliary tract cancer, wherein the presence or absence of biliary tract cancer in a subject is detected by measuring enzymatic activity specific to biliary tract cancer in a body fluid sample from the examined subject, and wherein the absence of the said enzymatic activity indicates the absence of biliary tract cancer whereas the presence of the said enzymatic activity indicates the presence of biliary tract cancer, wherein the measurement of the said enzymatic activity is performed using the compound having formula 1:

• wherein X1 comprises or consists of molecule C1 and X2 comprises or consists of molecule C2,
• wherein the pair of molecules C1 and C2 is a pair of fluorescence donor and fluorescence acceptor,
• and wherein the said compound undergoes enzymatic cleavage into the fragments X1-Glu-Arg-Arg-Ala-OH (fragment 1) and X2 (fragment 2) with the generation of a measurable optical signal upon spatial separation of molecules C1 and C2.