title: Immunohistochemistry of p53 and Ki-67 and p53 mutation analysis in renal epithelioid angiomyolipoma.
abstract: BACKGROUND
  Renal epithelioid angiomyolipoma (EAML) is a rare variant of AML (angiomyolipoma) and is often associated with aggressive behaviors. The pathogenesis of EAML has been poorly understood. We analyzed the expression of p53 and Ki-67 by immunohistochemistry (IHC) and investigated p53 mutation analysis in 11 cases of EAML in comparison to classical AML.
  
  
  METHODS
  P53 and Ki-67 expression status were determined by IHC staining. P53 mutation analysis was performed using bi-directional sequencing.
  
  
  RESULTS
  Renal EAML tumors were significantly associated with more severe to moderate nuclear atypia (100% vs. 36.4%, P = 0.004) and mitotic activity (90.9% vs. 27.3%, P = 0.008) compared with AML tumors. Out of 11 cases of EAML, 8 were positive for p53. There was only 1 case with positive p53 expression in AML cases and expression of p53 protein showed significant difference between EAML and AML tumors (72.7% vs. 9.1%, P = 0.008). In addition, there were 7 AML and 6 EAML cases harbored P72R mutation (SNP) in exon 4 of p53. Compared with AML cases, 2 out of 11 cases of EMAL showed more than 10% positivity for ki-67. The finding of stronger p53 expression in renal EAML might have contributed to their malignant behavior. However, the abnormal p53 expression cannot be entirely explained by p53 mutations in the exons examined.
  
  
  CONCLUSIONS
  Thus, the combination of immunohistochemical assessment of tumor antigens might improve our ability to predict the malignant outcome in EAML.
authors.affiliation: Department of Pathology, Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100021, China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Pathology, Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100021, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Guo
authors.affiliation: Department of Urology, Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100021, China.
authors.forename: Xingang
authors.initials: X
authors.lastname: Bi
authors.affiliation: Department of Urology, Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100021, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Pathology, Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100021, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zheng
mesh_terms: D000328:Adult; D018207:Angiomyolipoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004252:DNA Mutational Analysis / Q000379:methods; D015622:Epithelioid Cells / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D007680:Kidney Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53
keywords: EAML; Ki-67; immunohistochemistry; mutation analysis; p53