Molecular Marker Predicts Breast Cancer Prognosis

A predictive marker has been identified that will help doctors decide whether breast cancer patients would benefit from chemotherapy.

Breast cancer is heterogeneous and the existing prognostic classifiers are limited in accuracy, leading to unnecessary treatment of numerous women. B-cell lymphoma 2 (BCL2), an antiapoptotic protein, has been proposed as a prognostic marker, but this effect is considered to relate to estrogen receptor (ER) status.

Immunohistochemical analysis of BCL2 protein expression is a simple, well validated, inexpensive, and widely available test used routinely in diagnostic pathology of low-grade lymphoproliferative disorders. Immunostaining, with specific antibodies, can identify levels of BCL2 protein expression in tissue samples.

In a study, carried out at the University of Cambridge, (Cambridge, UK), 11,212 patients were examined who had early-stage breast cancer and had already received treatment. It took into account other predictive markers such as tumor size and grade, whether the cancer had spread to the lymph nodes and the state of estrogen receptors. The results indicated that BCL2 was an independent indicator of favorable prognosis for all types of early-stage breast cancer. This study establishes the rationale for introduction of BCL2 immunohistochemistry to improve prognostic stratification. Further work is now needed to ascertain the exact way to apply BCL2 testing for risk stratification and to standardize BCL2 immunohistochemistry for this application.

Sarah-Jane Dawson, M.D., lead author of the study, said, "There are a limited number of tools used to assess prognosis in women diagnosed with early stage breast cancer. New markers are urgently needed. BCL2 provides important additional prognostic information that may help guide decision making related to the use of chemotherapy.” The results of the study were published in the July 2010 issue of the British Journal of Cancer.

This is the first time this molecular marker has been singled out as an independent factor in examining a breast cancer patient's tumor. The study found that the more the marker BCL2 was present in a patient with early stage breast cancer, the more likely they were to survive.

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