Human epidermal growth factor receptor 2 (HER2), a known driver of some breast cancers, is amplified in the micropapillary urothelial carcinoma form of bladder cancer, and this amplification is associated with a greater risk of death, according to the findings of a recent study.
HER2 amplification is more frequent in micropapillary urothelial carcinoma than in typical urothelial carcinoma, and patients with micropapillary carcinoma who have HER2 amplification have worse cancer-specific survival than those who do not, John C. Cheville, MD, a pathologist at the Mayo Clinic in Rochester, Minn., and colleagues summarized in their paper for Modern Pathology.
Dr. Cheville’s group reached this conclusion after reviewing pathologic material and data from persons undergoing cystectomy at the facility from 1980 to 2008. They identified amplification of HER2 (referred to as ERBB2 in the study) in 9 of 61 micropapillary carcinomas (15%) compared with 9 of 100 urothelial carcinomas (9%).
Patients with HER2 amplification in micopapillary carcinoma demonstrated a nearly threefold increased risk of bladder cancer death, a risk that remained significantly elevated on multivariate analysis. The researchers observed no association between cancer-specific survival and HER2 amplification in patients with urothelial carcinoma and no association between HER2 protein expression and survival.
Noting the likelihood of more aggressive tumors in patient with HER2-amplified micropapillary urothelial carcinoma, Dr. Cheville commented in a Mayo Clinic statement that these findings show it is critical for pathologists to recognize this type of bladder cancer and for providers to order the appropriate tests. He also suggested that the monoclonal antibody trastuzumab, a targeted treatment for HER2-positive breast cancer, may also eventually prove to be a useful therapy against micropapillary urothelial carcinoma.