ABCB1 Polymorphism Test Prior to Therapy with Docetaxel or Irinotecan

 

Docetaxel can be used to treat malignant tumors including:

(1) breast cancer

(2) non-small cell lung cancer

(3) metastatic prostate cancer

 

Irinotecan can be used to treat:

(1) metastatic colorectal cancer

 

The ABCB1 gene encodes MDR1 P-glycoprotein, which is a transporter for the adenosine triphosphate binding cassette (ABC).

 

A patient who is homozygous for the 1236C>T (C1236T) polymorphism of ABCB1 shows decreased clearance of these 2 drugs and their active metabolites compared to patients homozygous for the wild type or heterozygous for the polymorphism.

 

A patient who is homozygous for the 1236C>T polymorphism will have decreased clearance of doxetaxel or irinotecan. A usual dose of the drug may cause a toxic reaction. This can be avoided by administering a lower dose of the drug.