EGFR Levels Could Be an Early Sign of Breast Cancer
Last Updated: 2010-04-20 19:03:19 -0400 (Reuters Health)
WASHINGTON, D.C. (Reuters Health) - Elevated levels of epidermal growth factor receptor (EGFR) could be one of the first signs that a woman is developing breast cancer, according to research presented here at the American Association for Cancer Research 101st Annual Meeting.
In a study led by Dr. Christopher Li, of the Fred Hutchinson Cancer Research Center, Seattle, Washington, EGFR levels were significantly elevated in women who developed estrogen receptor positive breast cancer as early as 17 months before their diagnosis.
"For the past few years, we've been trying to discover and validate proteins in the blood that could be potentially useful for the early detection of breast cancer," he told Reuters Health. "Right now, the best available tool we have is mammography."
He and his team conducted biomarker discovery and validation experiments to examine a variety of proteins in blood samples from 420 subjects in the Women's Health Initiative Observational Study who went on to develop ER+ breast cancer and from 420 matched controls. Of several proteins that appeared to be related to breast cancer risk, the most important was EGFR.
The researchers then validated their findings in another 198 women with ER+ breast cancer and an equal number of controls.
When they compared the blood samples of the women with breast cancer to those of matched controls, they found that women who had the highest levels of EGFR had a 2.9-fold increased risk of developing breast cancer.
The investigators next stratified women according to whether or not they used hormone therapy consisting of estrogen plus progestin. Among current users, those with EGFR in the highest quartile had a 9.04-fold increased risk of developing ER+ breast cancer compared to women in the lowest EGFR quartile.
Among current users of estrogen plus progestin hormone therapy, the sensitivity of EGFR as a marker for ER+ breast cancer risk was 31%, with a specificity of 90%, Dr. Li said.
"At this point, EGFR would be insufficient to use as a single marker. It has some reasonable predictive properties that are probably on the order of what we see for prostate specific antigen, but this is only among women who are current estrogen plus progestin users," he commented.
Still, the study is important for two reasons, he said. "No prior studies have validated even one single breast cancer early detection biomarker in preclinical samples like we have in this study, so this is exciting for us."
The second is that there are many other candidates that are worthy of follow up. "Our results show that this line of research does seem to be promising. We hope to identify other proteins and then perhaps have a panel of markers, including EGFR, that could be useful," he said.
EGFR may also turn out to influence the predictive value of mammography, Dr. Li added. "It is possible that using a biomarker-based test and mammography together could improve the sensitivity and specificity of our current screening modalities," he said.
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