Farnaz Dadmanesh, MD, Laura H. Tang, MD, PhD, Joseph Chao, MD, and Heather L. McArthur, MD, MPH, discuss HER2/HER3 testing/treatment in breast, gastrointestinal, lung, and other cancers in this CME/CC activity titled, "Increasing Importance of HER2 and HER3 Testing in the Context of an Expanding Targeted Therapies Landscape for Breast, Gastrointestinal, Lung, and Other Cancers: Latest Updates and Practical Guidance for Pathologists." For the full presentation, downloadable practice aids, complete CME/CC information, and to apply for credit, please visit us at https://bit.ly/2XlnuFi. CME/CC credit will be available until April 2, 2021.