Introduction
tumor, breast cancers, breast cancer, Malignant astrocytoma, HER-2
TUMOR, MALIGNANT ASTROCYTOMA, METASTATIC BREAST CANCER, BREAST CANCER
Approximately 72% of breast cancers diagnosed are hormone receptor positive and HER-2 neu negative [Morphine, which is a µ-opioid receptor (MOR) agonist, promotes angiogenesis-dependent growth in estrogen-dependent human MCF-7 cell tumor xenografts in mice at physiologically relevant conditions [Naltrexone is an opioid antagonist that is eight times more active and three times longer acting as naloxone, and previously has been shown to have anti-tumor activity in neuroblastoma-inoculated mice [Naltrexone has also been studied in other tumor types in humans. Malignant astrocytoma patients treated with radiotherapy and oral naltrexone survived longer than patients treated with radiotherapy alone [The effects of naltrexone in breast cancer physiology are unknown. The purpose of this study was to determine the safety and efficacy of naltrexone for the treatment of metastatic breast cancer that is refractory to hormonal therapy.