Triple-negative breast carcinomas are a heterogeneous entity that differs between young and old patients.
OBJECTIVE
To compare the frequency and immunohistochemical profiles of triple-negative breast carcinomas in younger and older women.


RESULTS
We selected patients diagnosed with triple-negative breast carcinomas. The groups examined were women who were 35 years old or younger between 1997 and 2007 (n = 74) and, for comparison, women who were 60 years old or older (n = 19, consecutive cases). All formalin-fixed and paraffin-embedded tumor samples were reviewed and immunohistochemically stained for ER, PR, HER2, Ki-67 antigen, epidermal growth factor receptor, cytokeratin 5/6, p53, vimentin, CD117, and p63 using tissue microarrays blocks. Triple-negative breast carcinomas corresponded to 34.6% (74/213) of the carcinomas from the younger patients and 16.2% (19/117) of the carcinomas from the older patients (p = 0.002). No significant differences in the frequency of the basal phenotype were observed in the two patient groups based on CK5/6 and/or epidermal growth factor receptor expression (74.3% vs. 68.4%). However, triple-negative breast carcinomas in the older patients presented a higher frequency of CK5/6 expression compared to those of younger patients (42.1% vs. 9.6%; p = 0.005), whereas triple-negative breast carcinomas of younger patients had a higher expression level of epidermal growth factor receptor (71.6% vs. 47.3%).


CONCLUSIONS
These results show that there were significant molecular differences between the triple-negative basal-like breast carcinomas that were diagnosed in younger women and those that were diagnosed in older women. These findings may provide a basis for describing the more aggressive phenotype of the triple-negative breast carcinomas observed in younger women.
Department of Pathology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. filomena@usp.br
Filomena M
FM
Carvalho
Livia M
LM
Bacchi
Priscila P C
PP
Santos
Carlos E
CE
Bacchi
D000328:Adult; D000367:Age Factors; D001943:Breast Neoplasms / Q000737:chemistry / Q000453:epidemiology* / Q000473:pathology*; D002277:Carcinoma / Q000737:chemistry / Q000453:epidemiology* / Q000473:pathology*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000032:analysis; D053553:Keratin-6 / Q000032:analysis; D008875:Middle Aged; D010641:Phenotype
D053555:Keratin-5; D053553:Keratin-6