TP53 and neoplasm: In one study that performed systematic microdissection of epithelial and sarcomatoid components of renal cell carcinomas6, 21 tumours with mixed histology had sarcomatoid components harbouring a greater mutational load than paired epithelial components, as well as greater numbers of mutations of TP53, chromatin modifiers BAP1 and ARID1 and Hippo pathway gene FAT2. Overall, these studies displayed different pictures of sarcomatoid kidney cancers, and key events leading to sarcomatoid dedifferentiation remain unsettled.