In addition, a misclassification of metastatic breast cancer patients by as much as 10 percent prevents some people from receiving optimal therapy.

Lapatinib, an oral chemotherapy agent, inhibits both HER2 and EGRF receptors, leaving unanswered questions about which patients are more likely to benefit. Researchers at the Norris Comprehensive Cancer Center found that HER2 amplification ("HER2-positive"), but not EGRF expression, is correlated with responsiveness to lapatinib. Women with both high and low levels of HER2 amplification respond to lapatinib. However, women with HER2-negative metastatic breast cancers do not respond.

Women with HER2-postitive metastatic breast cancer who receive lapatinib and chemotherapy have shown an improvement of approximately 50 percent in progression-free survival when compared to chemotherapy alone. Unfortunately, high volume laboratories using laboratory technicians instead of pathologists to score gene amplification misclassify approximately 10 percent of HER2 amplified breast cancers as not amplified, preventing these patients from being candidates for lapatinib.

"I would like to see all women with breast cancer tested appropriately, using the best method and certified personnel, to assess the HER2 status of their breast cancer so the appropriate treatment can be selected," said Michael Press, M.D., Ph.D., Norris Comprehensive Cancer Center Harold E. Lee Chair in Cancer Research and lead author of the study.

Currently lapatinib is approved by the FDA for use only in women who have HER2-positive metastatic breast cancer who were previously treated with anthracyclines, trastuzumab and taxane.

aacr/

The BSGI for the study was conducted using a Dilon 6800 Gamma Camera, a high-resolution, small field-of-view gamma camera, optimized to perform BSGI. With BSGI, the patient receives a pharmaceutical tracing agent that is absorbed by all the cells in the body. Due to their increased rate of metabolic activity, cancerous cells in the breast absorb a greater amount of the tracing agent than the normal surrounding tissue and generally appear as "hot spots" on the BSGI image.

Dr. Brem has published many articles on breast cancer-related topics in her areas of interest, which include new technologies for the early diagnosis of breast cancer and BSGI.

"BSGI is an effective adjunct imaging modality for the diagnosis of breast cancer and has a promising role in the diagnosis of ILC," said Dr. Brem.