Patterns of HER2 expression and genomic correlates in lung cancer, with a focus on preanalytical variables impacting immunohistochemical staining results

HER2 IHC 3+ is seen in a small but clinically significant proportion of samples and is associated with a variety of co-occurring non-ERBB2 genomic alterations. Preanalytical variables including specimen fixation can significantly impact the assessment of HER2 expression via immunohistochemistry.