Table 4.

Common gene expression-based assays in breast cancer.

Assay Name	Clinical Use	Factors Being Evaluated	Patient Demographics	Scoring
MammaPrint	Prognostic, determines chance of recurrence	70 genes associated with breast cancer recurrence	Newly diagnosed invasive breast cancer patients of all ages, stage I, II, or operable III, negative or 1–3 positive lymph nodes, and tumor size up to 5 cm	“low risk” or “high risk”
Oncotype DX	Predictive and prognostic, predicts recurrence and benefit from chemotherapy, staging	21 genes: 16 cancer related and 5 reference genes	Early-stage, ER-positive, HER2-negative, negative or 1–3 positive lymph nodes, and tumor size smaller than 5 cm	Risk score (≤15, low-risk; 16–25, intermediate-risk; ≥26, high-risk).
PAM50	Predicts chance of metastasis and determines if chemotherapy is needed	50 genes	Postmenopausal women, ER-positive, HER2-negative, negative or 1–3 positive lymph nodes, and tumor size no larger than 5 cm	PAM50-based Prosigna risk of recurrence score: low or high
Breast Cancer Index	Predicts risk of recurrence and mortality in 5 years and whether the benefit of extended endocrine therapy for 5 years will reduce risk of recurrence	11 genes	Early-stage HR-positive, lymph node-negative or positive (1–3 nodes)	Prognostic result (percentage) and predictive result (“yes” or “no”)
EndoPredict Test	Predicts the likelihood of distant recurrence with 10 years after diagnosis	12 genes	Early-stage ER-positive, HER2-negative, lymph node negative or positive (1–3 nodes)	EPclin Risk Score (a number between 1.1 and 6.2) maps to a percentage risk of recurrence. The scores higher than 3.3287 are interpreted as high-risk, and lower than 3.3287 are interpreted as low-risk of recurrence.