Oncogene overexpression is a well-known ubiquitous mechanism of tumorigenesis.18 Several studies have shown that CaSR is overexpressed in breast cancer in patients’ specimens and in malignant cell lines compared to nonmalignant breast cells.6,7 More recent studies have implicated CaSR in breast cancer metastasis to the bone due to calcium stimulation of these receptors.10 In this study, we found that NPS-2143 treatment had significant anticancer effects on breast cancer cells which was represented by suppression of cell proliferation and stimulation of caspase-dependent apoptosis. Here, CASR is linked to breast cancer.