title: [Distinction between benign and malignant pheochromocytomas].
abstract: OBJECTIVE
  To investigate the differences in morphology, immunohistochemistry, DNA ploidy status, LOH and MSI of 11q13 and 1p between benign and malignant pheochromocytomas, and to find the marker or markers useful in distinction between benign and malignant pheochromocytoma or for predicting the malignant potential of this tumor.
  
  
  METHODS
  Twenty-two cases of clinically documented benign and malignant pheochromocytomas from the files of Peking Union Medical College Hospital were analyzed. Aside from histological study, Ki-67, p53, CgA, S-100, PCNA and survivin immunohistochemistry studies were performed. DNA ploidy status was assessed by flow cytometry on cell suspensions prepared from formalin-fixed, paraffin-embedded sections. Twelve tumors (7 benign and 5 malignant) with paired normal tissues were microdissected. Tumor and normal tissue DNA were extracted. The obtained DNAs and 8 microsatellite markers related to 11q13 and 1q were subjected to PCR amplification for analysis of LOH and MSI.
  
  
  RESULTS
  None of the tumors showed atypical mitosis, only 1 malignant tumor had a mitotic count > 1/10 HPF (2.3/10 HPF). Two malignant tumors exhibited confluent necrosis. Ki-67 index was low in benign tumors (average 0.73%), and high in malignant tumors (average 2.4%). The difference of Ki-67 index between benign and malignant tumors was statistically significant. DNA ploidy status did not correlate with malignancy. Although LOH and/or MSI of 11q13 and 1p were observed in several tumors, a statistically significant difference could not be reached due to the small number of tumors analyzed.
  
  
  CONCLUSIONS
  Only Ki-67 index (> 3%) is an useful marker for distinguishing benign from malignant or for predicting the malignant potential of pheochromocytoma.
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Tong-Hua
authors.initials: TH
authors.lastname: Liu
authors.forename: Yuan-Jia
authors.initials: YJ
authors.lastname: Chen
authors.forename: Sha-Fei
authors.initials: SF
authors.lastname: Wu
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Jiang
authors.forename: Zhao-Hui
authors.initials: ZH
authors.lastname: Lu
authors.forename: Jian
authors.initials: J
authors.lastname: Guan
authors.forename: Shuan-Zeng
authors.initials: SZ
authors.lastname: Wei
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Luo
authors.forename: Jin-Ling
authors.initials: JL
authors.lastname: Cao
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Wan
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010673:Pheochromocytoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016133:Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53