ER Expression Predicts Breast Cancer Response to Radiation Treatment

The measurement of estrogen receptor (ER) predicts response to radiation therapy in breast cancer.

AQUA technology is an automated, quantitative immunohistochemistry (IHC) testing method that enables measurement of protein biomarkers in tissue as an aid to a pathologist's diagnosis. AQUA analysis is used in cancer research and is part of the clinical development plans for more than ten drug candidates from major pharma companies.

A study of 568 patients treated at the University of Calgary (Calgary, Canada) was designed to assess the objectivity and reproducibility of AQUA technology across institutions and across instrument platforms. It found that AQUA analysis, unlike any other system for measurement of in situ protein expression, can be standardized across platforms, operators, and staining runs.

ER testing services using AQUA analysis are currently available from Genoptix Inc. (Carlsbad, CA, USA), which licensed the technology from HistoRx (Branford, CT, USA) for this application.

Scientists from the HistoRx Inc. and the University of Calgary demonstrated that quantification of ER expression by AQUA analysis can provide a continuous recurrence risk assessment for breast cancer patients being treated with tamoxifen; low level ER expressing patients show significant benefit from radiation treatment whereas radiation treatment showed no benefit in high-level ER-expressing patients; and response to radiation treatment could be predicted by quantification of ER expression.

The study was selected for discussion on December 11, 2010, by breast cancer specialists assembled at the annual San Antonio Breast Cancer Symposium (Texas, USA).

Tony Magliocco, MD, associate professor in the departments of pathology and laboratory medicine and oncology at the University of Calgary, one of the authors of the study, stated, "Laboratories throughout North America have discovered a significant lack of reproducibility in ER testing, and the AQUA platform may provide a solution to the problem."

The evaluation was conducted on a cohort of retrospectively collected breast cancer specimens from patients treated with tamoxifen with or without radiotherapy. The investigators hope to confirm the clinical findings in a second study with a prospectively assembled patient population, ideally from a cooperative group or other multiinstitutional trial.

Related Links:
Genoptix Inc.
HistoRx
University of Calgary
San Antonio Breast Cancer Symposium