For instance, we recently uncovered a novel role for miR-181a in promoting breast cancer metastasis and showed that the expression of this metastamiR correlates with the metastatic potential of breast cancers, particularly those classified as triple-negative (i.e., lack ER-α and progesterone receptor expression, and fail to amplify HER2) [108]. The gene discussed is PGR; the disease is breast carcinoma.