Dean Fennell, PhD, FRCP, University Hospitals of Leicester NHS Trust, Leicester, UK, shares results from the Phase II MiST trial (NCT03654833) which is investigating personalized medicine approaches to the treatment of malignant mesothelioma. Prof. Fennell comments on results from Arm 1, exploring use of the PARP inhibitor rucaparib in patients with mesothelioma, as well as the use of BAP1, BRCA1 and alternative mutations as predictors of response. This interview took place during the 19th British Thoracic Oncology Group (BTOG) Annual Conference 2021.