The EAI test is a gene expression profile (GEP) test that measures transcriptional activity related to Estrogen Receptor (ER) and Progesterone Receptor (PR) in breast cancer tumor tissue to yield an EAI Score.
Expression of 18 genes representing ER and PR activity is measured in a tumor sample from core biopsy or surgical resection
The ER/PR activity index is further adjusted for baseline prognosis using molecular subtype genes (RNA4 signature) and the clinical factors of tumor size and regional lymph node involvement to yield the Endocrine Activity Index (EAI) score.
The analytical and clinical validity of the EAI test has been established through multiple prospective retrospective studies from randomized clinical trials.
These studies have shown that the EAI is:
A consistent prognostic indicator for long term outcomes (DFS, EFS or DRFS) in Stage II-III breast cancer patients
Independent from other prognostic tests available on the market
Predictive for response to dose-intense chemotherapy in the 12-year outcomes analysis of the CALGB 9741 trial
Two Main Applications for EAI Test
Prognostic for 5-year disease-free survival in Stage II/III, HR+ patients on standard-of-care therapy
Predictive of survival benefit from dose-intense chemotherapy in Stage II/III, HR+ patients, independent of menopausal status
Endocrine Activity Index Development Timeline:
EAI is known in scientific publications as the Sensitivity to Endocrine Therapy (SET) Test (includes both SETER/PR and SET2,3 Indexes).