These 20 miRNAs have been already described in early studies identifying miRNAs implicated in breast cancers [7, 9, 15, 17] but miR-190b retained our attention because it was the only miRNA strongly up-regulated in ER+ compared to ER− breast tumors with a FC of 23 much higher than all other up-regulated miRNAs. Here, ESR1 is linked to breast cancer.