PIK3CA and undifferentiated carcinoma: To explore the effect of chemotherapy on A2BR expression, we treated TNBC cell lines MDA-MB-231 (invasive ductal carcinoma cell line with BRAF, CDKN2A, KRAS, and TP53 mutation), SUM149 (inflammatory ductal carcinoma cell line with BRCA1 mutation), and SUM159 (anaplastic carcinoma cell line with PIK3CA and TP53 mutation) with Food and Drug Administration (FDA)-approved chemotherapy drugs paclitaxel and carboplatin for 72 h at the IC50 of the drug, and found that each of these chemotherapeutic drugs increased A2BR protein levels in all these cell lines (Figure 1A).