title: Peroxisome proliferator-activated receptor gamma expression in follicular-patterned thyroid lesions. Caveats for the use of immunohistochemical studies.
abstract: To determine its usefulness as a specific diagnostic marker for follicular carcinomas (FCs) vs other follicular-patterned thyroid lesions and possible application to fine-needle aspiration specimens, we immunohistochemically studied peroxisome proliferator-activated receptor gamma (PPAR gamma) expression in histologic sections (FC, 13 cases; follicular adenoma [FA], 11; follicular variant of papillary carcinoma [FVPC], 9) and surrounding thyroid tissue by using a PPAR gamma monoclonal antibody. Positivity (detected by nuclear staining) was scored as absent, weak, moderate, or strong. When only moderate or strong nuclear staining was considered positive, 9 FCs (69%), 3 FAs (27%), and 2 FVPCs (22%) demonstrated positive nuclear immunoreactivity. The sensitivity and specificity of immunohistochemical detection of PPAR gamma expression in FCs were 69% and 75%, respectively. In nonlesional surrounding tissue, moderate to strong positive staining was seen in focal areas of chronic lymphocytic thyroiditis in 6 of 33 cases (FC, 2; FA, 3; FVPC, 1); diffuse moderate staining was detected in surrounding tissue in the absence of lymphocytic thyroiditis in 4 cases (12%; FC, 3; FA, 1). Staining in the follicular-patterned lesions and surrounding nonlesional thyroid was specific with peptide blocking experiments. PPAR gamma expression is not a specific marker for FCs, and its detection in nonlesional thyroid tissue suggests limited usefulness as a diagnostic marker for follicular-patterned lesions in general.
authors.affiliation: Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, USA.
authors.forename: Karen S
authors.initials: KS
authors.lastname: Gustafson
authors.forename: Virginia A
authors.initials: VA
authors.lastname: LiVolsi
authors.forename: Emma E
authors.initials: EE
authors.lastname: Furth
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Pasha
authors.forename: Mary E
authors.initials: ME
authors.lastname: Putt
authors.forename: Zubair W
authors.initials: ZW
authors.lastname: Baloch
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D000236:Adenoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis / Q000378:metabolism; D002291:Carcinoma, Papillary / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D014157:Transcription Factors / Q000032:analysis / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors