Methods for measuring the insulin receptor alpha subunit

Abstract

Presence of free insulin receptor α-subunit in blood was discovered. Furthermore, methods for measuring the insulin receptor α-subunit was provided, the method comprising the steps of contacting the insulin receptor α-subunit in a blood sample with an antibody recognizing the insulin receptor α-subunit, and detecting the binding between the two. Measurement of the free insulin receptor α-subunit in the blood is useful for evaluating risk factors for diabetes. In addition, the measurement methods of the present invention showed that concentrations of the free insulin receptor α-subunit in the blood of diabetes or cancer patients are significantly high. Free insulin receptor α-subunit in blood is useful as a marker for diabetes or cancer.

1 . A method for diagnosing cancer, wherein the method comprises the steps of:
 (a) measuring the amount of a free insulin receptor α-subunit in a biological sample of a subject;   (b) comparing the amount of the free insulin receptor α-subunit with that of a cutoff value; and   (c) determining the subject to have cancer when the amount of the free insulin receptor α subunit in the biological sample of the subject is greater than that of the cutoff value.   
     
     
         2 . The method for diagnosis of  claim 1 , wherein the biological sample is a blood sample. 
     
     
         3 . The method for diagnosis of  claim 2 , wherein the amount of the free insulin receptor α subunit is measured by a method comprising the steps of:
 (1) contacting a blood sample with an antibody recognizing the insulin receptor α subunit; 
 (2) detecting binding of said antibody to the insulin receptor α-subunit present in blood; and 
 (3) determining the amount of free insulin receptor α-subunit in blood based on the level of binding detected between said antibody and subunit. 
 
     
     
         4 . The method for diagnosis of  claim 1 , wherein the cancer is selected from the group consisting of lung cancer, esophageal cancer, pancreatic cancer, colon cancer, breast cancer, liver cancer, rectal cancer, or skin cancer.