Up to date, a potent anticancer effect of nonspecific adenosine deaminase inhibitor, erythro‐9‐(2‐hydroxy‐3‐nonyl)adenine (EHNA), was indicated against malignant pleural mesothelioma, but the effect of a specific ADA inhibition on the breast cancer development has never been studied.19 The gene discussed is ADA; the disease is breast cancer.