ESR1 and breast cancer: To identify target genes that are clinically relevant in ER+ breast cancer, and also highly correlated with LINC02568, we first queried the expression of those 206 genes in GEPIA2 database, which led to the identification of 18 genes that are expressed significantly higher in ER+ breast tumor tissues than normal tissues (FC ≥ 2, p ≤ 0.01) (Figure 3F and Table S3, Supporting Information).