title: Tartrate-resistant acid phosphatase 5b as a serum marker of bone metastasis in breast cancer patients.
abstract: Diagnosis and follow-up of bone metastases in breast cancer patients usually rely on symptoms and imaging studies. Tartrate-resistant acid phosphatase 5b (TRACP 5b) is a specific marker of osteoclasts and is herein proposed as a marker of bone metastasis in breast cancer patients. An immunoassay using a monoclonal antibody, 14G6, was used to measure the activity of serum TRACP 5b at pH 6.1 in 30 early breast cancer patients without bone metastasis and in 30 aged-matched breast cancer patients with bone metastasis. Another 60 normal volunteers were recruited as controls. Bone alkaline phosphatase (BAP), a traditional marker of bone turnover, was also measured in selected cases. The overall mean TRACP 5b activity in normal women was 2.83 +/- 1.1 U/l, and it increased with age. The mean TRACP 5b activity in early breast cancer patients did not differ from that of the normal group (2.93 +/- 0.64 vs. 2.83 +/- 1.1 U/l; p = 0.66), whereas it was significantly higher in breast cancer patients with bone metastasis (5.42 +/- 2.5 vs. 2.83 +/- 1.1 U/l; p < 0.0001). BAP activity was significantly higher in breast cancer patients with bone metastasis than in early breast cancer patients (p = 0.004). Serum TRACP 5b activity correlated well with BAP activity in breast cancer patients with bone metastasis (p < 0.0001), but not in normal individuals or in patients without bone metastasis. TRACP 5b activity can be considered a surrogate indicator of bone metastasis in breast cancer patients.
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC. j0607@ms6.hinet.net
authors.forename: Tsu-Yi
authors.initials: TY
authors.lastname: Chao
authors.forename: Ching-Liang
authors.initials: CL
authors.lastname: Ho
authors.forename: Su-Huei
authors.initials: SH
authors.lastname: Lee
authors.forename: Mary Mei-Ju
authors.initials: MM
authors.lastname: Chen
authors.forename: Anthony
authors.initials: A
authors.lastname: Janckila
authors.forename: Lung T
authors.initials: LT
authors.lastname: Yam
mesh_terms: D000135:Acid Phosphatase / Q000097:blood*; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D001943:Breast Neoplasms / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000175:diagnosis; D011379:Prognosis; D012680:Sensitivity and Specificity; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D000469:Alkaline Phosphatase; C000605510:ACP5 protein, human; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase