IHC staining can be used to screen for ROS1 gene rearrangements, with patients herein showing a response to crizotinib. Patients with tumors that test positive according to IHC staining but negative according to FISH were also identified, which may have implications for treatment selection.

No abstract

There are significant differences in PD-L1 expression in relation to histological patterns, with particularly high levels in those with pleomorphic features and low/undetectable levels in invasive mucinous adenocarcinomas and the lepidic components of non-mucinous adenocarcinomas. Assessment of PD-L1 expression in a resected adenocarcinoma with a lepidic component may therefore not be reliable when immumodulatory therapy for recurrent disease is being considered, and either re-biopsy or limiting assessment to the invasive component may be more appropriate.

Human papillomavirus (HPV)-associated oropharyngeal carcinoma is now recognized as a clinically distinct subtype of head and neck cancer with important prognostic implications. HPV testing is recommended as the standard of care for all patients diagnosed with oropharyngeal squamous cell carcinoma. Here, we describe a practical approach to HPV testing within the setting of the diagnostic histopathology laboratory.