Aside from reports of retained PTH mRNA expression mentioned above, Posada-González et al. described an NFPC occurring in a MEN2A patient with a germline heterozygous RET Cys618Arg mutation, and Khalil et al. reported a case with activating PIK3CA and frameshift MEN1 mutations, along with partial parafibromin loss—but without CDC73 mutation analysis [37, 42]. This evidence concerns the gene MEN1 and multiple endocrine neoplasia type 2A.