We found that the expression of the two-base 5′-extension isomiR of hsa-miR-423-3p was significantly higher in tumor compared with normal tissue (p = 0.00023, Figure 3C) across all tumor subtypes and ethnic backgrounds, and in a subset of hormone-receptor-positive patients (estrogen-receptor-positive, ER+, or progesterone-receptor-positive, PR+) in the white population (p = 0.0047). This evidence concerns the gene ESR1 and neoplasm.