ESR1 and breast cancer: After successful cultivation of breast cancer organoids, it is necessary to identify from multiple dimensions, such as morphology, histopathology, and molecular genetics, whether tumor organoids can restore the morphological phenotype and tumor biomarkers of the original tumor (37), such as the most common tumor markers in breast cancer: estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, to ensure the credibility of subsequent organoid drug sensitivity test results.