Such drugs affected metastasis more than proliferation, according to Cancer Research paper.
Cancer Research study says EGFR inhibitors can obstruct the promotional effects of hormones produced by fat cells.
Researchers at Emory University School of Medicine report that epithelial growth factor receptor (EGFR) inhibitors could be effective in treating breast cancer patients who are obese.
In the laboratory, EGFR inhibitors blocked the stimulatory effects of the hormone leptin and insulin-like growth factor-1 (IGF-1). Studies also showed that they had more of an effect on breast cancer cells’ ability to migrate and invade other tissues than on proliferation. This suggests they could blunt aggressive, metastatic tumor behavior. Leptin and IGF-1 are both found at elevated levels in obese patients and together seem to promote breast cancer cell growth and migration more than either factor alone.
“The influence of obesity on breast cancer is more pronounced because most of the breast tissue is made of adipocytes,” says Dipali Sharma, Ph.D., professor of oncology/hematology. “There is an increasing amount of evidence for the importance of the environment surrounding the tumor in spurring its growth.”
Since inhibiting either leptin or IGF-1 by itself would only take care of a part of the issue, investigators decided to target the point where the two pathways converge –the EGFR molecule.
A range of EGFR inhibitors such as erlotinib and cetuximab are approved to treat various cancers. One, lapatinib, was approved in 2007 for women with advanced breast cancer who had already received other therapies. But previous clinical studies found that most EGFR inhibitors were not effective against breast cancer for a large enough proportion of patients, according to the Emory Univ. research team.
The team believes however that this recent research may help a specific fraction of patients, those with triple negative breast cancer, a form that does not respond to tamoxifen or the drug trastuzumab. Scientists are planning more tests in animals that model cancer growth in obese individuals and to study leptin and IGF-1 levels in human tumor samples.
The study is published online in the December issue of Cancer Research.