The purpose of the current systematic review and meta-analysis was to assess the predictive value of RS results for response to NET in patients diagnosed with ER+/HER2-breast cancer on their core tissue biopsy, and the most important finding is data indicating patients with low or intermediate RS are estimated to be four times more likely to achieve a response to NET than those with high-risk RS. The gene discussed is ESR1; the disease is breast carcinoma.