HER3 Alterations in Cancer and Potential Clinical Implications

SIMPLE SUMMARY: HER3 is a member of the HER family. In the past decade, HER3 has been recognized as an important protein in allowing tumors to grow unchecked. This review focuses on HER3′s involvement in bladder, breast, colorectal, and lung cancers. In addition, this review covers what is known about HER3 alterations or mutations in bladder, breast, colon, and lung cancers. Finally, therapies that target HER3 are discussed. ABSTRACT: In recent years, the third member of the HER family, kinase impaired HER3, has become a target of interest in cancer as there is accumulating evidence that HER3 plays a role in tumor growth and progression. This review focuses on HER3 activation in bladder, breast, colorectal, and lung cancer disease progression. HER3 mutations occur at a rate up to ~10% of tumors dependent on the tumor type. With patient tumors routinely sequenced for gene alterations in recent years, we have focused on HER3 mutations in bladder, breast, colon, and lung cancers particularly in response to targeted therapies and the potential to become a resistance mechanism. There are currently several HER3 targeting drugs in the pipeline, possibly improving outcomes for cancer patients with tumors containing HER3 activation and/or alterations.