RET and neoplasm: Additionally, testing for microsatellite instability (MSI), mismatch repair (MMR) status, tumour mutational burden (TMB), and other relevant markers, such as folate receptor alpha (FRα), B-rapidly accelerated fibrosarcoma (BRAF) gene alternation, neurotrophic tyrosine receptor kinase (NTRK) and rearranged during transfection (RET) gene alternation, is crucial if these were not included in previous assessments.