Establishment and characterization of phosphaturic mesenchymal tumor cell line

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15591561
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Orthopaedic surgery
• Research Institution: Tohoku University
• Principal Investigator: HATORI Masahito Tohoku University, Hospital, Lecturer, 病院, 講師 (70208552)
• Co-Investigator(Kenkyū-buntansha): UMEDA Mika (WATANABE Mika) Tohoku University, Hospital, Research Associate, 病院・助手 (20292344) ; TOYOSAWA Satoru Osaka University, Graduate School of Dentistry, Professor, 大学院・歯学研究科, 教授 (30243249)
• Project Period (FY): 2003 – 2004
• Keywords: phosphaturic mesenchymal tumor / dentin matrix protein 1 / lung metastasis / immunohistochemistry

Research Abstract

Phosphaturic mesenchymal tumors (PMTs) produce oncogenic osteomalacia. In the present case, a PMT was located in the lower leg with lung metastasis. 15 years were taken before arriving at the correct diagnosis. The clue to the diagnosis lies in paying close attention to the low serum phosphate levels in patients suffering generalized symptoms of weakness and osteomalacia. Histological examination revealed a hypercellular spindle cell neoplasm with chondroid material, irregular calcification and hyaline collagenous fibers. We xenografted small pieces of the excised tumor into the back of nude mice in order to establish a cell line of PMT but no tumor growth was found. We focused to characterize the excised tumor morphologically, immunohistochemically and genetically. Dentin matrix protein 1(DMP 1) was expressed in the lung lesion as well as the primary tumor. Reverse transcription polymerase chain reaction detected DMP 1 and FGF 23. DMP1 immunohistochemistry is thought to be very useful for differentiating PMT from other tumors.