Abstract
BACKGROUND/AIM: Sarcomas of the breast are extremely rare malignant tumors and comprise only 5% of all sarcomas and fewer than 1% of breast cancers. Primary osteosarcoma of the breast is histologically indistinguishable from osteosarcoma of the bone. Effective therapies of this recalcitrant disease have not yet been developed. MATERIALS AND METHODS: A patient-derived xenograft (PDX) mouse model of primary osteosarcoma of the breast was established by subcutaneous implantation of the surgical specimen, along with surrounding normal tissue. Hematoxylin and eosin (H&E) staining was performed on paraffin-embedded histological sections of the original tumor resected from the patient and from implanted tumors that grew in nude mice. RESULTS: Tumors grew in 46 of 51 mice implanted with the original surgical specimen. The H&E-stained slides of the mouse-grown tumor and the original patient tumor matched, both showing large areas of spindle-shaped cells, characteristic of osteosarcoma. CONCLUSION: The first PDX mouse model of primary breast osteosarcoma was established which will enable testing of novel therapeutics as well as basic research of osteosarcoma of the breast.