Coordinated expression of ER, PR and HER2 define different prognostic subtypes among poorly differentiated breast carcinomas.
OBJECTIVE
Histological grade is one of the most important prognostic factors in breast carcinomas, but poorly differentiated neoplasms still have quite heterogeneous biological behaviour, since they can be genetically classified as basal-like, HER2+ or even luminal. The aim was to analyse the frequency of oestrogen receptor (ER), progesterone receptor (PR) and HER2 expression profiles among breast carcinomas with <10% tubular formation, and their correlation with classic prognostic factors.


RESULTS
One hundred and thirty-four samples of paraffin-embedded tumours were studied retrospectively. The tumours were classified in to four groups by their ER/PR/HER2 profile: (i) ER+ and/or PR+ but HER2-; (ii) ER+ and/or PR+ and HER2+; (iii) ER- and/or PR- but HER2+; and (iv) ER-, PR- and HER2- (triple-negative). The histological features of triple-negative and HER2+ carcinomas overlap. The only difference was the expression of basal cytokeratins (basal CK), which was more frequent among triple-negative carcinomas. Basal-CK expression defined a more aggressive group of tumours, according to the pathological features, regardless of the immunohistochemical profile.


CONCLUSIONS
Group 1 and 2 tumours (ER+ and/or PR+ tumours with or without HER2 expression) were not statistically different, suggesting that poorly differentiated carcinomas with hormone receptors correspond to the luminal B type of tumour. Among poorly differentiated breast carcinomas, the classic profile associated with basal-CK identifies distinct subtypes equivalent to those seen by genetic classification.
Fernandes
Raquel C M
RC
Department of Pathology, Universidade de São Paulo, SP 01246-903, Brazil.
Bevilacqua
Jose L B
JL
Soares
Ibere C
IC
Siqueira
Sheila A C
SA
Pires
Luis
L
Hegg
Roberto
R
Carvalho
Filomena M
FM
D002288:Adenocarcinoma, Mucinous / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology*; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000378:metabolism; D008875:Middle Aged; D009336:Necrosis; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012189:Retrospective Studies; D046888:Tissue Array Analysis; D055815:Young Adult
D014408:Biomarkers, Tumor; D007633:Keratins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human