ESR1 and neoplasm: ,13 In contrast, GSE20194, a component of the MicroArray Quality Control Consortium Project II, comprises tumor samples resected after six months of NAC, including regimens with paclitaxel, 5-fluorouracil, cyclophosphamide, and doxorubicin, thereby enabling the evaluation of intratumoral ER-positive cell proportion in relation to treatment response.14