Intrinsic subtype-associated changes in the plasma proteome in breast cancer

Area of Science:

• Oncology
• Proteomics
• Biochemistry

Background:

• Breast cancer comprises five intrinsic subtypes: Luminal A, Luminal B, HER2+, Basal, and Normal-like.
• Plasma proteome alterations may serve as biomarkers for specific breast cancer subtypes.

Purpose of the Study:

• To compare the plasma proteome of patients with Luminal A, Luminal B, HER2+, and Basal breast cancer subtypes against healthy individuals.
• To identify subtype-specific protein expression changes in breast cancer patients.

Main Methods:

• Plasma samples from patients with Luminal A, Luminal B, HER2+, and Basal breast cancer subtypes were analyzed.
• Plasma samples from healthy individuals served as controls.
• Proteomic analysis was performed, with significant changes defined by a false discovery rate (q-value) below 5%.

Main Results:

• Luminal B and Basal breast cancer subtypes exhibited the most significant changes in plasma proteome compared to healthy controls.
• The plasma proteomes of Luminal A and HER2+ breast cancer patients showed no significant differences from healthy individuals.
• Basal breast cancer was associated with downregulation of numerous plasma proteins, while Luminal B showed upregulation of acute phase-response proteins (α-glycoprotein orosomucoid 1, serum amyloid protein P) and downregulation of immune response and free radical scavenging proteins.

Conclusions:

• Plasma proteome profiles are distinct for different breast cancer intrinsic subtypes.
• Specific protein changes in Luminal B and Basal subtypes may indicate low-grade inflammation and immune system alterations.
• These findings highlight the potential of plasma proteomic analysis for understanding breast cancer progression and systemic effects.