A comprehensive morphological study for basal-like breast carcinomas with comparison to nonbasal-like carcinomas.
BACKGROUND
Breast carcinomas can be classified into five subtypes based on gene expression profiling or immunohistochemical characteristics. Among these subtypes, basal-like breast carcinomas (BLBCs) are one of the most studied group, due to their poor prognosis. The aim of this study was to investigate the prevalance, morphological and immunohistochemical features of BLBCs, in Turkish population.


METHODS
Five hundred invasive breast carcinomas were reviewed for several morphological features and immunostained for oestrogen and progesterone receptors, c-ERB-B2, cytokeratin5/6, cytokeratin14, vimentin and epidermal growth factor receptor (EGFR). Basal-like breast carcinoma was defined as a triple negative tumor with cytokeratin5/6 and/or EGFR positive.


RESULTS
The prevalance of BLBC was 9.6%. All medullary carcinomas and 55.6% of metaplastic carcinomas showed basal-like immunophenotype. Patients with BLBC were younger (p=0.04) and had higher-grade tumors (p<0.0001). Morphologic features associated with BLBC included increased mitosis, nuclear pleomorphism, presence of geographic and/or central necrosis, pushing margin of invasion and stromal lymphocytic response (p<0.0001). Presence of prominent nucleoli and vesicular nuclear chromatin were the cytological features correlated with basal-like phenotype (p<0.0001). On multivariate analyses, BLBCs were associated with high mitotic number (p<0.0001), the presence of vesicular chromatin (p=0.004), high tubular grade (p=0.011), lymphocytic response (p=0.031) and the absence of carcinoma insitu (p=0.039). Vimentin was positive in 53.2% of BLBCs, while cytokeratin14 was less frequently expressed (27.7%).


CONCLUSIONS
BLBCs have some distinctive, but not pathognomonical, morphological features. Paying attention to these features and adding cytokeratin14 and vimentin to the immunohistochemical panel can help the definitive diagnosis of BLBCs.
Http://www.diagnosticpathology.diagnomx.eu/vs/5962175467857400.
Department of Pathology, Gazi University School of Medicine, Besevler 06500, Ankara, Turkey. erdoganasli@gmail.com
Asli
A
Cakir
Ipek Isik
II
Gonul
Omer
O
Uluoglu
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000145:classification* / Q000453:epidemiology / Q000473:pathology*; D002277:Carcinoma / Q000737:chemistry / Q000145:classification* / Q000453:epidemiology / Q000473:pathology*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D015994:Incidence; D016015:Logistic Models; D008875:Middle Aged; D008940:Mitotic Index; D015999:Multivariate Analysis; D009336:Necrosis; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D016017:Odds Ratio; D010641:Phenotype; D011237:Predictive Value of Tests; D015995:Prevalence; D014421:Turkey / Q000453:epidemiology; D055815:Young Adult
D014408:Biomarkers, Tumor