title: Glucocorticoid receptor expression in 20 solid tumor types using immunohistochemistry assay.
abstract: BACKGROUND
  Glucocorticoid receptor (GR) activity plays a role in many aspects of human physiology and may play a crucial role in chemotherapy resistance in a wide variety of solid tumors. A novel immunohistochemistry (IHC) based assay has been previously developed and validated in order to assess GR immunoreactivity in triple-negative breast cancer. The current study investigates the standardized use of this validated assay to assess GR expression in a broad range of solid tumor malignancies.
  
  
  METHODS
  Archived formalin-fixed paraffin-embedded tumor bank samples (n=236) from 20 different solid tumor types were analyzed immunohistochemically. Nuclear staining was reported based on the H-score method using differential intensity scores (0, 1+, 2+, or 3+) with the percent stained (out of at least 100 carcinoma cells) recorded at each intensity.
  
  
  RESULTS
  GR was expressed in all tumor types that had been evaluated. Renal cell carcinoma, sarcoma, cervical cancer, and melanoma were those with the highest mean H-scores, indicating high levels of GR expression. Colon, endometrial, and gastric cancers had lower GR staining percentages and intensities, resulting in the lowest mean H-scores.
  
  
  CONCLUSIONS
  A validated IHC assay revealed GR immunoreactivity in all solid tumor types studied and allowed for standardized comparison of reactivity among the different malignancies.
  
  
  CONCLUSIONS
  Baseline expression levels of GR may be a useful biomarker when pharmaceutically targeting GR in research or clinical setting.
authors.affiliation: Corcept Therapeutics, Inc, Menlo Park, CA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA.
authors.forename: Thaddeus S
authors.initials: TS
authors.lastname: Block
authors.affiliation: QualTek Molecular Laboratories, Newtown, PA.
authors.forename: Tiffany I
authors.initials: TI
authors.lastname: Murphy
authors.affiliation: Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Pamela N
authors.initials: PN
authors.lastname: Munster
authors.affiliation: Corcept Therapeutics, Inc, Menlo Park, CA.
authors.forename: Dat P
authors.initials: DP
authors.lastname: Nguyen
authors.affiliation: QualTek Molecular Laboratories, Newtown, PA.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Lynch
keywords: glucocorticoid receptor expression; immunohistochemistry; solid tumors