Figure 7.
Deficient Brg1 or HDAC2 expression in Cushing disease corticotroph adenomas. Immunohistochemical analysis of the corticotroph marker TPIT (A,D,G,J), Brg1 (B,E,H,K), and HDAC2 (C,F,I,L) in representative corticotroph adenomas. (A–C) Tumor revealed by nuclear TPIT staining (A) with normal nuclear Brg1 (B) and nuclear HDAC2 (C). (D–F) Tumor with cytoplasmic Brg1 (E) and normal nuclear HDAC2 (F). Note nuclear Brg1 in contiguous normal tissue. (G–I) Tumor with no nuclear Brg1 (H) and normal nuclear HDAC2 (I). (J–L) Tumor with normal nuclear Brg1 (K) and no nuclear HDAC2 (L). Each row presents data from one patient who is representative of the others in the same group as summarized in M. Human patients were subdivided into moderate or complete Gc resistance groups depending on their response to low or high doses of dexamethasone. In 19 cases, expression of Brg1 and HDAC2 were similar in tumor and normal pituitary tissues. Overall, 17 of 36 patients (47%) present with abnormal expression of Brg1 or HDAC2. The panel of 12 dog corticotroph adenomas (Supplementary Fig. S2) had four with no or low Brg1 expression and two with no tumor Brg1 and low HDAC2.