Fig 1: Inactive CASR/GABBR heteromer formation is favored in tumors from vitamin D-deficient PHPT patients. (A) Protein abundance of CASR, GABBR1, and GABBR2 was determined in situ from parathyroid tissue sections using a NanoString DSP instrument and a custom conjugated antibody panel. The relative abundance of the individual proteins and the ratio of CASR to the GABBA receptor proteins were determined in sections from vitamin D-deficient patient tumors (DEF), vitamin D-replate patient tumors (REP), or normal donor parathyroid tissue (NORMAL). (B) The ratio of CaSR protein to GABBR proteins was determined in the indicated cell types and tissue sources. Green bars = normal tissue. Orange bars = tumors from vitamin D-deficient patients. Blue bars = tumors from vitamin D-replete patients. Hashmarked bars = chief cells. Plain bars = oxyphil cells. Values shown are the means ± standard deviation for each sample group. n = 6 (normals), n = 13 (replete), and n = 6 (deficient).