title: Primary squamous cell carcinoma of the breast with unusual basal-HER2 phenotype.
abstract: OBJECTIVE
  To report three cases of primary squamous cell carcinoma of the breast with an unusual "basal-HER2" phenotype.
  
  
  METHODS
  Clinical data were analyzed. Morphological features were observed. Immunohistochemical study for ER, PR, HER2, Ki-67, CK 5/6, CK10/13, CK14, EGFR, P63 and FISH detection of HER2 gene amplification were performed.
  
  
  RESULTS
  Three patients were all female with 26, 57 and 66 years old. The tumors were 3 cm, 4 cm and 5 cm in size respectively. Morphologically, all three tumors were pure squamous cell carcinoma and entirely composed metaplastic squamous cells. Two tumors were moderately differentiated and one was poorly differentiated. All three patients were positive for P63 or CK10/13. All three tumors exhibited basal-HER2 phenotype: negative for ER and PR, positive for HER2 protein and HER2 gene amplification, and positive for at least two basal markers.
  
  
  CONCLUSIONS
  SCC with basal-HER2 phenotype is an extremely rare subset of breast carcinoma. Since it may have worse prognosis than typical basal-like SCC, recognization of this unusual SCC in routine work may have obvious clinical significance.
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Ruohong
authors.initials: R
authors.lastname: Shui
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Anqi
authors.initials: A
authors.lastname: Li
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Baohua
authors.initials: B
authors.lastname: Yu
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Pathology, Cancer Center, Fudan University; Department of Oncology, Fudan University Shanghai, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D005260:Female; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D010641:Phenotype; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases
keywords: Squmous cell carcinoma; basal-HER2 phenotype; breast cancer