title: Serum cross-linked n-telopeptides of type 1 collagen (NTx) in patients with solid tumors.
abstract: OBJECTIVE
  Cross-linked N-telopeptides of type I collagen (NTx) increase in concentration in situations in which bone resorption is increased, such as osteoporosis and bone metastasis (BM). We aimed to evaluate the serum concentrations of NTx in a sample of patients with several types of solid tumors.
  
  
  METHODS
  Cross-sectional analytical study with a control group in a tertiary public hospital.
  
  
  METHODS
  We performed the quantitative enzyme-linked immunosorbent assay (ELISA) on serum NTx levels in 19 subjects without a history of cancer and 62 patients with various solid tumors who had been referred for a bone scan. Three experienced analysts read all bone scans.
  
  
  RESULTS
  The serum NTx levels in patients with cancer and BM, with cancer but without BM and without cancer were 46.77 +/- 2.58, 32.85 +/- 2.05 and 22.32 +/- 2.90 respectively (P < 0.0001). We did not find any significant correlations of serum NTx with age, gender, history of bone pain, tumor type and bone alkaline phosphatase levels. We found a significant correlation between serum NTx and alkaline phosphatase levels (R(2) = 0.08; P = 0.022).
  
  
  CONCLUSIONS
  Serum NTx levels are significantly higher in patients with solid tumors and bone metastases than they are in patients without bone metastases and in normal controls.
authors.affiliation: Fundação e Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Jablonka
authors.forename: Fernanda
authors.initials: F
authors.lastname: Schindler
authors.forename: Paula Philbert
authors.initials: PP
authors.lastname: Lajolo
authors.forename: Hélio
authors.initials: H
authors.lastname: Pinczowski
authors.forename: Fernando Luiz Affonso
authors.initials: FL
authors.lastname: Fonseca
authors.forename: Antônio
authors.initials: A
authors.lastname: Barbieri
authors.forename: Luiz Henrique
authors.initials: LH
authors.lastname: Massonetto
authors.forename: Fábio Tadashi
authors.initials: FT
authors.lastname: Katto
authors.forename: Auro
authors.initials: A
authors.lastname: Del Giglio
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D001859:Bone Neoplasms / Q000097:blood* / Q000556:secondary; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology; D002277:Carcinoma / Q000097:blood* / Q000473:pathology; D024042:Collagen Type I / Q000097:blood*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology
chemical_list: D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D000469:Alkaline Phosphatase