PTH and tumor of parathyroid gland: While we did not observe significantly reduced PTH mRNA levels in parathyroid tumor cells compared to normal tissue, our experimental design utilized a cross-sectional panel of independent normal donor glands as a reference standard rather than tumor-adjacent histologically normal parathyroid cells that may be influenced by the adjoining tumor (60) or parathyroid glands obtained from thyroid carcinoma patients undergoing thyroidectomy (61).