Dicer has an important role in the regulation of cell number and in controlling apoptosis.1, 2, 3 Loss of Dicer in mice disrupts embryonic stem-cell differentiation and is lethal during early development.4 Low Dicer expression is associated with worse clinical outcomes in lung cancer,5 breast cancer,6 and endometrial adenocarcinoma.7 Low expression of Dicer and Drosha is associated with ovarian cancer progression and poor clinical outcomes.8 The gene discussed is DICER1; the disease is breast cancer.