The evolution of gene expression profiling in breast cancer – A narrative review

Gene expression profile has revolutionised breast cancer treatment. It has paved the way for developing cancer-specific treatment and predicting the chances of recurrence. Genomic analysis has set the benchmark for personalised cancer therapy. The gene signature tests are mainly used in hormone-positive or luminal breast carcinoma with no or low lymph nodal metastatic carcinoma, and it helps in preventing unnecessary usage of chemotherapy in low-risk groups. The low and high gene expression profiles have made inroads into the new prognostic staging of breast cancers. There are several commercially available gene signature prognostic tests such as 21-Gene Recurrence Score (RS) assay (Oncotype DX), predictor analysis of microarray 50 risk of RS, Amsterdam 70-gene Profile (MammaPrint), Breast Cancer Index and EndoPredict. The gene signature assay can be useful in stratifying hormone-positive breast cancer patients into low and high genomic risk category. The low genomic risk patients can avoid unnecessary use of chemotherapy