title: Associations of epithelial c-kit expression in phyllodes tumours of the breast.
abstract: BACKGROUND
  Mammary phyllodes tumours (PT) are rare biphasic neoplasms but have important clinical significance. Both epithelial and stromal components participate in PT development. Despite a number of studies on stromal c-kit in PT, little is known about the role of its epithelial expression.
  
  
  OBJECTIVE
  To further evaluate the stromal and epithelial expression of c-kit in a cohort of patients with PT.
  
  
  RESULTS
  Expression of c-kit in both epithelial and stromal components was examined and correlated with histological features in PT. Stromal c-kit expression was associated positively with stromal cellularity (median expression=10.0, 30.0 and 50.0 from mild to severe cellularity; p=0.019). Conversely, a significant negative trend between epithelial c-kit expression with stromal pleomorphism (median expression=55.0, 30.0 and 2.5 from mild to severe pleomorphism; p=0.043) and mitosis (median expression=70.0 and 20.0 for low and high mitosis respectively; p=0.003); and a trend of negative correlation with increased PT grade was found. Despite these reverse associations, epithelial and stromal c-kit expressions were positively correlated with each other. Notably, the correlation of stromal c-kit expression with malignant histological features appeared to be stronger in cases with low epithelial c-kit expression but not in those with high epithelial c-kit expression.
  
  
  CONCLUSIONS
  This study demonstrated the association of epithelial c-kit expression with stromal histological features and stromal c-kit. Interestingly, epithelial c-kit expression affected the strength of the correlation of stromal c-kit with these histological features. These findings provide further evidence of the interaction between the epithelial and stromal components in PT.
authors.affiliation: Department of Pathology, University of the Philippines, Manila, Philippines.
authors.forename: John
authors.initials: J
authors.lastname: Tawasil
authors.affiliation: Department of Pathology, University of the Philippines, Manila, Philippines.
authors.forename: Edna May L
authors.initials: EM
authors.lastname: Go
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Julia Y S
authors.initials: JY
authors.lastname: Tsang
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Yun-Bi
authors.initials: YB
authors.lastname: Ni
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Chun-Wai
authors.initials: CW
authors.lastname: Ko
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Tse
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology; D004847:Epithelial Cells / Q000737:chemistry* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D008938:Mitosis; D008940:Mitotic Index; D060787:Neoplasm Grading; D003557:Phyllodes Tumor / Q000737:chemistry* / Q000473:pathology; D011237:Predictive Value of Tests; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis*; D017154:Stromal Cells / Q000737:chemistry / Q000473:pathology; D046888:Tissue Array Analysis; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D019009:Proto-Oncogene Proteins c-kit
keywords: BREAST PATHOLOGY; IMMUNOHISTOCHEMISTRY; c-kit expression