CD274 and mismatch repair cancer syndrome 1: Concerning new targeted therapies, a subset of PAs that display high tumor mutation burden (TMB), PD-L1 expression, microsatellite instability, or MMR deficiency may respond to immunotherapy [21,22,23,24,25,26,27,28,29,30,31,32,33,34,61,62,63,64,65].