Clinical significance of neuroendocrine carcinoma of the breast.
BACKGROUND
Neuroendocrine (NE) carcinomas of the breast are defined by the diffuse expression of NE markers. This definition includes lesions with 'pure' NE phenotype as well as 'variants' which may co-express mucinous and/or apocrine phenotype. In the present work, the clinical significance of pure' NE differentiation in breast carcinoma and of its 'variants' will be analyzed.


METHODS
Forty-three NE breast carcinomas immunocytochemically positive for chromogranins and/or synaptophysin in > or = 50% of cells were graded following the Elston and Ellis grading system for breast carcinomas. The production of mucin and the expressionof the apocrine marker Gross Cystic Disease Fluid Protein-15 (GCDFP-15) were correlated with the grade and the hormonal receptor status. The clinical outcome of patients was also analyzed.


RESULTS
The histological grade highly influenced the clinical evolution of NE breast carcinomas. We confirmed that mucinous differentiation is an important indicator of low biological aggressiveness. Estrogen and progesterone receptor expression was also correlated with a better prognosis. Presence of androgen was correlated with the expression of GCDFP-15 in NE tumors.


CONCLUSIONS
The histological grade overcomes the immunophenotype in determining the prognosis of NE differentiated carcinomas of the breast. Co-expression of exocrine products in such tumors is related to hormone dependency.
Sapino
A
A
Department of Biomedical Sciences and Human Oncology, University of Turin, Italy. anna.sapino@unito.it
Papotti
M
M
Righi
L
L
Cassoni
P
P
Chiusa
L
L
Bussolati
G
G
D001053:Apolipoproteins; D053399:Apolipoproteins D; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000276:immunology / Q000473:pathology*; D002352:Carrier Proteins / Q000032:analysis; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis*; D005260:Female; D005500:Follow-Up Studies; D006023:Glycoproteins; D006801:Humans; D007150:Immunohistochemistry; D026901:Membrane Transport Proteins; D009077:Mucins / Q000096:biosynthesis; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000276:immunology / Q000473:pathology*; D010641:Phenotype; D011379:Prognosis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D016019:Survival Analysis
C024328:APOD protein, human; D001053:Apolipoproteins; D053399:Apolipoproteins D; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D053379:Chromogranin A; D002864:Chromogranins; D006023:Glycoproteins; D026901:Membrane Transport Proteins; D009077:Mucins; C488892:PIP protein, human; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone