CCND1 and parathyroid gland adenoma: The molecular pathogenesis of sporadic parathyroid adenomatosis is complex (25) not only involving mutations in CCND1/PRAD1, CDC73/HRPT2, MEN1, CaSR (25–27) and several other genes identified by the next-generation sequencing techniques (28) but also involving epigenetic alterations such as DNA methylation and histone modifications in sporadic parathyroid adenoma (29–31).