Parathyroid tumors are associated with parathormone (PTH) hypersecretion defining the endocrine disease hyperparathyroidism. Primary hyperparathyroidism is associated with bone and kidney complications. Though mainly benign, parathyroid tumor-related hyperparathyroidism occurs in up to 2% of post-menopausal women, making it the third most common endocrine disorder following diabetes and thyroid diseases. Parathyroid tumorigenesis is far to be elucidated and effective alternative treatments to surgery are limited. Parathyroid tumours show a great variability both in clinical features, such as the severity of PTH secretion, the rate and the pattern of cell proliferation, and genetic background. Studies aiming to develop new diagnostic markers and therapeutic approaches need a deeper definition of this variability. Dysregulation of the methylation pattern, of the microRNAs (miRNAs) and long non coding RNAs (LncRNAs) is under investigation in our Lab with the collaboration of researchers from Milan, Pisa and San Giovanni Rotondo (FG) in Italy.