title: Differential immunohistochemical and biological profile of squamous cell carcinoma of the breast.
abstract: BACKGROUND
  Pure or metaplastic squamous cell carcinoma (SCC) of the breast is a rare entity with an unclear pathogeny and aggressive clinical behaviour. An attempt was made to characterize its differential immunohistochemical and biological profile.
  
  
  METHODS
  Twenty-seven cases of SCC (pure or not) of the breast were matched with 27 ductal invasive carcinomas (IDC) for age, tumour size, nodal involvement and year of diagnosis. The expression levels of oestrogen receptor (ER), progesterone receptor (PR), Ki-67, epidermal growth factor receptor (EGFR), HER2, Cyclin Bl, hTERT, cytokeratins (CK) 5/6 and p63 were determined immunohistochemically in both cohorts. The presence of the human papilloma virus (HPV) genome was investigated by polymerase chain reaction (PCR).
  
  
  RESULTS
  Pure and metaplastic SCC displayed common profiles typifying a basal origin: they never expressed ER or PR, were HER2-negative in 93% of cases, exhibited positivity for CK5/6 or EGF-R in 75% and 85%, and for p63 in 70% of cases and were highly proliferative. These profiles were markedly different from those of matched controls (p<0.001 for five markers) except for HER2 and hTERT. The HPVgenome was detected in 2 out of 14 cases (14%) of SCC.
  
  
  CONCLUSIONS
  The expression profile of SCC of the breast was markedly different from that of IDC. A typical "basal-like" phenotype was displayed that may explain part of their behaviour and justify specific therapeutic approaches. HPV infection was not a leading oncogenic event in SCC of the breast.
authors.affiliation: Department of Medical Oncology, Institut Gustave Roussy, 39 rue Camille Desmoulins, 94805 Villejuif. julien.grenier@hmn.aphp.fr
authors.forename: Julien
authors.initials: J
authors.lastname: Grenier
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Soria
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Mathieu
authors.forename: Fabrice
authors.initials: F
authors.lastname: Andre
authors.forename: Selma
authors.initials: S
authors.lastname: Abdelmoula
authors.forename: Valerie
authors.initials: V
authors.lastname: Velasco
authors.forename: Luc
authors.initials: L
authors.lastname: Morat
authors.forename: Benjamin
authors.initials: B
authors.lastname: Besse
authors.forename: Ariane
authors.initials: A
authors.lastname: Dunant
authors.forename: Marc
authors.initials: M
authors.lastname: Spielmann
authors.forename: Suzette
authors.initials: S
authors.lastname: Delaloge
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D052685:Alphapapillomavirus / Q000235:genetics; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D015331:Cohort Studies; D004268:DNA-Binding Proteins / Q000032:analysis; D066246:ErbB Receptors / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000032:analysis; D053553:Keratin-6 / Q000032:analysis; D019394:Ki-67 Antigen / Q000032:analysis; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000378:metabolism / Q000473:pathology / Q000821:virology; D016133:Polymerase Chain Reaction; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D016019:Survival Analysis; D015534:Trans-Activators / Q000032:analysis; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D053555:Keratin-5; D053553:Keratin-6; D019394:Ki-67 Antigen; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C115051:TP63 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D066246:ErbB Receptors