Triple negative breast carcinomas: similarities and differences with basal like carcinomas

Area of Science:

• Oncology
• Molecular Biology
• Genomics

Background:

• Breast cancer classification is essential for treatment and prognosis.
• Gene expression profiling via cDNA microarrays categorizes breast cancers into distinct molecular subtypes.
• Basal-like breast carcinoma is a recognized subtype with specific characteristics.

Purpose of the Study:

• To detail the classification of breast cancers using cDNA microarrays.
• To characterize the basal-like breast carcinoma subtype.
• To identify reliable markers for basal-like breast carcinoma diagnosis.

Main Methods:

• Utilized cDNA microarrays for gene expression analysis.
• Examined expression patterns of cytokeratins (CKs) and other markers.
• Correlated gene expression profiles with clinical and pathological features.

Main Results:

• Identified six breast cancer groups: luminal A, B, C, normal breast-like, human epidermal growth factor receptor 2-positive, and basal-like.
• Basal-like tumors express basal cytokeratins and often lack hormone receptors and human epidermal growth factor receptor 2.
• Cytokeratin 5 (CK5) demonstrated high concordance (around 80%) with triple-negative breast carcinomas and is a key identifier, alongside CK14, CK17, and epidermal growth factor receptor.
• A subset of triple-negative breast carcinomas exhibits myoepithelial differentiation.

Conclusions:

• cDNA microarrays provide robust classification of breast cancers into clinically relevant subtypes.
• Basal-like breast carcinomas are distinct and can be identified by specific cytokeratin markers, particularly CK5.
• Further research suggests a potential origin of basal-like carcinomas from mammary stem cells.