Patient samples were obtained with informed consent and utilized in accordance with UConn Health Institutional Review Board approved protocols and policies of the University of Connecticut. Eighty-two cases of sporadic parathyroid adenoma were selected for this study according to the following criteria: (i) referral for parathyroidectomy following a diagnosis of biochemical PHPT, that is, hypercalcemia with elevated or inappropriately normal parathyroid hormone levels; (ii) absence of personal or family history suggestive of a heritable or syndromic form of parathyroid disease; (iii) single-gland lesion resected at parathyroidectomy, and (iv) histological confirmation of a high-purity, adenomatous tumor free of any atypical or malignant features. Median patient age was 59 at the time of parathyroidectomy (range 19–90). The cohort included 59 females, 21 males, and 2 samples where gender was not noted in deidentified pathology reports. Apart from the need to have adequate quantity of tissue available for research, and quality of samples for study, cases were otherwise unselected in terms of clinical or demographic criteria.

Tumor DNA was isolated from fresh frozen patient tumor samples by proteinase K digestion, phenol-chloroform extraction, and ethanol precipitation. Matched germline DNA was isolated from peripheral blood using PureGene Blood Kit (Qiagen) or from muscle tissue using the phenol-chloroform method.