RESUMO
This study investigated triple negative diagnoses that occurred in 27 (11%) out of 243 cases of breast cancer analyzed for the presence of estrogen receptor (ER), progesterone receptor( PgR), and human epidermal growth factor receptor 2 (HER 2). In 5 of the triple negative cases of breast cancer, the patients were young, under 35 years of age (average age of 29). In 22 of the cases, the women were 35 years or older (average age of 66). The cancer quickly reoccurred in 4 of the 5 cases of triple negative breast cancer in young women despite various chemotherapy treatments, and in 3 of those cases the women died within 14 months following surgery. Even in statistical analysis, triple negative breast cancer in young women has a significantly poorer prognosis for both disease-free survival rate and overall survival rate, compared with triple negative breast cancer in women 35 and older, and young women without triple negative breast cancer. When basal-like phenotype was defined as being positive for epidermal growth factor (EGFR) and/or cytokeratin (CK)5/6, among the triple negative breast cancer cases of women 35 years and older, the rate for basal-like phenotype, which is said to have a poor prognosis, was 67% (14 out of 21 cases) while in young women with triple negative breast cancer, all cases (5 out of 5) were basal-like phenotype. This suggests that the biological degree of malignancy is extremely high for young women with triple negative breast cancer.