title: [Quantitative analysis of circulating DNA in serum of cancer patients].
abstract: OBJECTIVE
  To develop a method for ng quantitation of circulating DNA in serum and explore the value in the diagnosis of cancer.
  
  
  METHODS
  Serum DNA was extracted by commercial "genomic DNA extraction kit" and detected by fluorescent dye (SYBR green I) staining. Loss of heterozygosity (LOH) at BRCA1 (D17S579, D17S855) and p53 (TP53, D17S786) in serum DNA was analyzed by PCR-based method.
  
  
  RESULTS
  SYBR green I dot staining could detect DNA as low as 2 ng. Using this method, we detected serum samples from 483 patients with various types of cancer and 150 healthy individuals. The mean DNA concentration in the normal controls was 22.2 +/- 13.4 ng/ml, while that in cancer patients was 81.3 +/- 98.3 ng/ml (P < 0.001). In 33 ovarian cancer patients with increased DNA level, 27(81.8%) displayed LOH in at least one of the four loci analyzed.
  
  
  CONCLUSIONS
  Circulating DNA in serum may become additional tumor marker for the diagnosis of cancer.
authors.affiliation: Shanghai Cancer Institute/Cancer Institute of Shanghai Jiao-Tong University, Shanghai 200032, China. tuhong66@yahoo.com
authors.forename: Hong
authors.initials: H
authors.lastname: Tu
authors.forename: Hai-feng
authors.initials: HF
authors.lastname: Gao
authors.forename: Shi-long
authors.initials: SL
authors.lastname: Fu
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
mesh_terms: D019313:BRCA1 Protein / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000097:blood; D004273:DNA, Neoplasm / Q000097:blood* / Q000235:genetics; D005260:Female; D019398:Genes, BRCA1; D016158:Genes, p53; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D009369:Neoplasms / Q000097:blood* / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: D019313:BRCA1 Protein; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D016159:Tumor Suppressor Protein p53