Histological specimens are recommended to assess a patient’s PD-L1 status; however, it is not always easy or even feasible to secure a histological specimen in advanced cancers such as stage IV NSCLC. Cytological specimens are typically used in this setting to assess other molecular markers such as ALK or ROS1 – should they also be used to assess PD-L1 status?This episode summarises the evidence for and against a cytological approach, before joining Professor Frederique Penault-Llorca for her opinion on whether cytology should be used to assess PD-L1 status in real-world practice.References:Gosney J, et al. Lung Cancer. 2020; Heymann J, et al. Cancer Cytopathology. 2017; 125(12): 896-907Wagner C, et al. Eur Respir J. 2018; 52: Suppl. 62, PA2217.Access more free education today! Visit the website, follow us on Twitter (@onckip) or connect on LinkedIn.This independent educational activity is supported by an educational grant from Merck, Sharpe & Dohme Corp. The educational content has been developed by Liberum IME in conjunction with an independent steering committee; MSD corp. has had no influence on the content of this education.