Table 2 Main features of the principal available multi-gene assays in breast cancer

Sample

Tissue core of fresh specimens preserved in RNA later or fresh-frozen tissue

Formalin-fixed, paraffin- embedded tissue, or fresh-frozen tissue

Formalin-fixed, paraffin- embedded tissue, or fresh-frozen tissue

Technique

DNA microarray

Quantitative PCR

Quantitative PCR and nCounter technology

Study population

Patients <61 years, with T1-T2, N0 disease (largely ER-positive)

Patients with ER-positive, node-negative disease

Patients with stage I to III breast cancer

Output

Low- or high-risk patients

Recurrence score: low, intermediate, or high

Risk of recurrence: low, medium, or high

Guidelines

FDA-approved

National Comprehensive Cancer Network, American Society of Clinical Oncology

FDA-cleared

Clinical applications

Accurate and reproducible representation of BC biological features [7]. Overall risk assessment of BC recurrence [8]. BluePrint and MammaPrint improve stratification of patients in the neoadjuvant setting [14,16].

Accurate and reproducible representation of BC biological features [7]. Overall risk assessment of BC recurrence [8]. Prognostic role in tamoxifen-treated patients with positive nodes [13]. Prediction of CMF efficacy in ER-positive, node-negative BC patients [13]. Prediction of FAC efficacy in ER-positive, node-positive BC patients [7].

Accurate and reproducible representation of BC biological features [7]. Categorization of tumors into the four intrinsic subtypes [8,9]. Prediction of DFS and OS [9]. Estimate of the risk of relapse at 5 to 15 years in ER-positive, node-positive and -negative BC [10]. Prediction of benefit of tamoxifen in pre-menopausal patients [9].