Background: Docetaxel (DOC) is inactivated by CYP3A4, high expression of which in tumor tissue might serve as a resistance mechanism. In the present study, the CYP3A4 protein level in breast cancers was determined by immunohistochemistry, and its relationship with the response to DOC treatment was studied.
Materials and Methods: Thirty-one patients with locally advanced (n = 21) or recurrent (n = 10) breast cancers underwent tumor biopsy, followed by DOC treatment (60 mg/m² q3w). Expression of CYP3A4 was studied by immunohistochemistry.
Results: Patients with CYP3A4 negative tumors (n = 15) by immunohistochemistry showed a significantly (P < 0.01) higher response rate (67%) to DOC treatment than those with CYP3A4 positive tumors (n = 16, 19%). The positive predictive value, negative predictive value, and diagnostic accuracy of CYP3A4 expression by immunohistochemistry in the prediction of response to DOC were 67%, 81%, and 74%, respectively.
Conclusion: Immunohistochemical analysis of CYP3A4 expression in tumor cells might be clinically useful in the prediction of tumor response to DOC.

This article cannot obtain the latest cited-by information.