title: Cathepsin K expression in a wide spectrum of perivascular epithelioid cell neoplasms (PEComas): a clinicopathological study emphasizing extrarenal PEComas.
abstract: OBJECTIVE
  Recent studies have demonstrated that cathepsin K seems to be a powerful marker in identifying renal perivascular epithelioid cell neoplasms (PEComas). However, the expression in extrarenal PEComas has not been well characterized due to their rare incidence. Our aim was to investigate the expression of cathepsin K in a wide spectrum of extrarenal PEComas and evaluate its potential diagnostic usefulness in comparison with other commonly used markers.
  
  
  RESULTS
  Twenty-three cases of PEComa (liver, n = 9; lung, n = 1; broad ligament of uterus, n = 1; vertex subcutaneous soft tissue, n = 1; abdominal wall, n = 1; and kidney, n = 10) were selected for study. All displayed a high percentage of cells with moderately to strongly positive reactions for cathepsin K (mean 91%; range 80-100%). HMB45, Melan-A and smooth muscle actin (SMA) were expressed in 78, 87 and 87% of cases, respectively, with various percentages of positive cells (mean, 34, 40 and 38%; range 0-80, 0-90 and 0-90%). Transcription factor E3 (TFE3) was expressed strongly in only three cases; none exhibited evidence of TFE3 gene fusion or amplification.
  
  
  CONCLUSIONS
  Cathepsin K appears to be more powerful than other commonly used markers in diagnosing a wide spectrum of PEComas and distinguishing them from the majority of human cancers.
authors: Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
authors: Qiu
authors: Q
authors: Rao
authors: Liang
authors: L
authors: Cheng
authors: Qiu-yuan
authors: QY
authors: Xia
authors: Biao
authors: B
authors: Liu
authors: Li
authors: L
authors: Li
authors: Qun-li
authors: QL
authors: Shi
authors: Shan-shan
authors: SS
authors: Shi
authors: Bo
authors: B
authors: Yu
authors: Ru-song
authors: RS
authors: Zhang
authors: Heng-hui
authors: HH
authors: Ma
authors: Zhen-feng
authors: ZF
authors: Lu
authors: Pin
authors: P
authors: Tu
authors: Xiao-jun
authors: XJ
authors: Zhou
mesh_terms: D000328:Adult; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D001956:Broad Ligament / Q000473:pathology; D056657:Cathepsin K / Q000378:metabolism*; D002452:Cell Count; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000201:enzymology* / Q000473:pathology; D008113:Liver Neoplasms / Q000201:enzymology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D054973:Perivascular Epithelioid Cell Neoplasms / Q000201:enzymology* / Q000473:pathology; D014594:Uterine Neoplasms / Q000201:enzymology* / Q000473:pathology; D055815:Young Adult
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D014408:Biomarkers, Tumor; C069203:TFE3 protein, human; C534130:CTSK protein, human; D056657:Cathepsin K