Histamine and Bone Pain Association in Participants With Breast Cancer Metastatic in the Bone

PRIMARY OBJECTIVES: I. To correlate levels of histamine in plasma with pain scores in patients with bone metastases from breast cancer that have or have not been treated with palliative radiotherapy. SECONDARY OBJECTIVES: I. To perform exploratory studies with additional markers not mentioned, including calcitonin gene-related peptide (CGRP), stem cell factor (SCF), angiotensin II (Ang II) substance P, angiotensin 1-7 (Ang1-7), may be performed at the investigator's discretion. II. To perform next generation ribonucleic acid (RNA) sequences using the whole blood to determine whether histamine system is involved in the development of cancer-induced bone pain (CIBP). III. To assess the impact of pain response after radiotherapy on bone structural properties such as bone mineral density and cortical thickness, and patient quality of life, physical and psychological function. OUTLINE: Participants undergo collection of blood samples for histamine level analysis via enzyme-linked immunosorbent assay (ELISA). After completion of study, participants are followed up at 1, 3, and 6 months.