ARID1A and breast cancer: Neoadjuvant chemotherapy (NAC) is used in breast cancer treatment of downstage tumours.21 We analysed the transcriptional profile of ARID1A in breast tumours derived from breast cancer patients receiving preoperative paclitaxel‐based NAC by using GSE22513 data set.22, 23, 24ARID1A mRNA levels in breast tumours derived from patients with no pathological complete response (nCR) were significantly lower than those from patients with pathological complete response (pCR) (Figure 5E).