Researchers propose a breast cancer drug for bladder cancer patients

Volume 3, Issue 2, 2014

Summary

A treatment for HER2-positive breast cancer may also work for HER2-positive bladder cancer, a Mayo Clinic study finds.

Photograph of John C. Cheville, M.D., a Mayo Clinic pathologist

John C. Cheville, M.D.

Researchers at the Mayo Clinic Cancer Center have found amplification of the HER2 gene in a type of bladder cancer called micropapillary urothelial carcinoma (MPUC). They have shown that the presence of HER2 amplification is associated with particularly aggressive tumors.

The HER2 gene is a known driver of some breast cancers. These findings suggest that administering the drug trastuzumab to MPUC patients with HER2 amplification could improve outcomes, just as it has for HER2-positive breast cancer.

The study was published in the Nov. 1, 2013, online edition of the journal Modern Pathology.

As it does in breast cancer, HER2 amplification in micropapillary urothelial carcinoma results in a faster growing cancer that spreads quickly and has a higher chance of recurrence. The hope is that combating this amplification with trastuzumab will result in effective therapy against bladder cancer.

"These findings show it is critical for pathologists to recognize this type of bladder cancer and that providers order the appropriate tests," said John C. Cheville, M.D., a Mayo Clinic pathologist and lead author of the journal article about the study. "This will be essential for any clinical trial examining the effectiveness of trastuzumab in treating MPUC."

The study identified HER2 amplification in 15 percent of patients with MPUC, compared with 9 percent of typical bladder cancers. Patients with HER2-amplified MPUC were more likely to have aggressive tumors than were patients whose tumors did not have HER2 amplification, according to this study.

"Targeted treatments for HER2-positive breast cancer have led to markedly improved survival," Dr. Cheville said. "In one sense, what we are trying to do with HER2-positive bladder cancer is a relatively simple thing. We are trying to identify prognostic and therapeutic biomarkers, and ultimately match the most effective drug to the individual patient's tumor, rather than its location in the body."

HER2 is an important target in breast cancer therapy, and gene amplification occurs in approximately 20 to 30 percent of cases, Dr. Cheville said. Using the latest molecular techniques, researchers in the Mayo Clinic Center for Individualized Medicine's Biomarker Discovery Program determined that some bladder cancers similarly show HER2 amplification and produce too much of the HER2 protein product, resulting in more rapid tumor growth and expansion.

Watch a video of Dr. Cheville discussing this study.