Molecular Testing in Breast Cancer: A Guide to Current Practices

Area of Science:

• Oncology
• Pathology
• Molecular Diagnostics

Background:

• Molecular diagnostics are integral to managing various cancers, notably breast cancer.
• Understanding breast cancer biology has advanced significantly with intrinsic subtyping.

Purpose of the Study:

• To update practicing pathologists on current molecular testing in breast cancer clinical practice.
• To provide a focused overview for non-specialists in breast cancer pathology.

Main Methods:

• This study employed a narrative literature review methodology.
• Information was gathered from existing scientific literature to synthesize current practices.

Main Results:

• Routine testing includes hormone receptor status and HER2 amplification/overexpression.
• Next-generation sequencing (tumor profiling) is increasingly utilized for actionable mutation identification.
• Multianalyte assays (e.g., MammaPrint, Oncotype DX, Prosigna) are prominent in breast cancer management.

Conclusions:

• Molecular testing, including HER2 and tumor profiling, is essential in breast cancer care.
• Multianalyte assays and genetic predisposition testing play significant roles.
• Intrinsic tumor subtyping, while biologically important, has an indirect clinical impact currently.