Breast cancer is considered today as a heterogeneous group of diseases, with a wide spectrum of clinical, pathologic and molecular features. A new classification of breast carcinomas, based on gene expression profiles technologies (cDNA microarray), shows impact on the diagnosis and prognostic classification of tumors, prediction of response of individual patients to specific chemotherapeutic regimens, and identification of novel tumor targets.
Aim: To identify the proportion of basal-like ("triple-negative") tumors in patients treated for breast carcinoma.
Objectives: To evaluate the impact of molecular subtyping on treatment response, disease-free survival and overall survival of patients, and to establish and correlate particular biologic, clinical and diagnostic features of these cancers.
Methods: 96 patients with breast cancer, aged 28-78 years, were retrospectively selected using specific criteria from cases treated between 2001 and 2007 in the Oncology Department of the "Sf. Spiridon" Hospital Iaşi. Tumors were divided into molecular subtypes using immunohistochemistry data.
Results: The most frequent pathology was ductal carcinoma (77 patients, 80.2%), and most tumors were intermediately or poorly differentiated (G2 43 patients, 44.8%; G3 37 patients, 38.5%) The proportion of basal-like tumors in the population sample analyzed was 15.62% (15 patients). Histological type (p=0.85), pTNM stage (p=0.618), and tumor differentiation grading (p=0.54) did not correlate with molecular subtype. Patients with basal-like tumors had lower time-to-progression (mean 31.2 months, 95%CI 18.5-43.8, p=0.005), disease free survival (mean 24.46 months, 95%CI 12.6-36.3, p=0.016), and overall survival (mean 39.26 months, 95%CI 26.7-51.7, p=0.023).
Conclusion: We have demonstrated, using the simple commonly available immunohistochemical markers ER, PR and HER2/neu, that patients with triple negative breast cancers have relatively poor prognosis, with significantly shorter survival and a poorer response to standard treatment strategies.