Circulating deoxyribonucleic Acid as prognostic marker in non-small-cell lung cancer patients undergoing chemotherapy.
Author(s): Gautschi O, Bigosch C, Huegli B, Jermann M, Marx A, Chassé E, Ratschiller D, Weder W, Joerger M, Betticher DC, Stahel RA, Ziegler A
Publication: J Clin Oncol, 2004, Vol. 22, Page 4157-64
PubMed ID: 15483026 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to compare DNA concentrations in serum and plasma from health individuals and those with non-small cell lung cancer (NSCLC). Effects of tube type, cancer stage, remission, leukocyte count and lactate dehydrogenase (LDH) levels were also explored.
Conclusion of Paper
Concentrations of cell-free DNA were significantly higher in serum than plasma, and in patients with NSCLC than in healthy controls. Both plasma and serum cell-free DNA concentrations were higher in patients with more advanced tumor stage than those with early-stage tumors. Serum DNA levels decreased when the patient went into remission and plasma DNA concentrations increased with disease progression. Serum DNA concentrations were modestly correlated with leukocyte counts, while plasma DNA concentrations were weakly correlated with LDH levels. The authors report that the yield of cell-free DNA from plasma and serum was comparable between specimens collected in Monovette and Vacutainer tubes.
Studies
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Study Purpose
The purpose of this study was to determine if different collection tube types, cancer stages, remission, leukocyte counts and LDH levels affect cell-free DNA concentrations in plasma and serum from patients with NSCLC and healthy individuals. Blood was obtained from 185 patients with NSCLC and 46 healthy individuals. Additional plasma and serum specimens were obtained at a follow-up visit from 65 and 66 of the original patients, respectively. Of the patients included in this subset, 26 were in remission and 25 had an unchanged disease status. Plasma and serum were obtained by two centrifugations at 1,500 x g and were stored at -70ºC. DNA was extracted using the QIAamp Blood mini kit and stored at -20ºC until quantification by real-time PCR amplification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
Summary of Findings:
The median DNA concentration was approximately 10-fold higher in serum than plasma both in patients with NSCLC (39.8 ng/mL versus 3.7 ng/mL) and healthy controls (12.6 ng/mL versus 1.8 ng/mL). Plasma and serum cell-free DNA concentrations were higher in patients with NCSLC than in healthy individuals (p<0.001, both). Although plasma and serum cell-free DNA concentrations were higher in patients with a more advanced tumor stage than those with early-stage tumors (p=0.003 and p=0.028, respectively), the difference in serum levels due to disease stage was less apparent than in plasma, as levels were elevated even at early stages. Serum DNA levels decreased when the patient went into remission (p=0.002), but no change was observed with disease progression. In contrast, plasma DNA concentrations were unaffected by remission, but increased with disease progression (p=0.006). Serum, but not plasma DNA concentrations were modestly correlated with leukocyte counts (r=0.529, p<0.001) and thus the authors attribute the higher DNA concentrations in serum than plasma to leukocyte lysis during clotting. Plasma DNA levels were weakly correlated with LDH levels (r=0.261, p=0.009), but a similar correlation was not observed for serum DNA concentrations. The authors report that the yield of cell-free DNA from plasma and serum were comparable between specimens collected in Monovette and Vacutainer tubes.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Normal
- Neoplastic - Carcinoma
Platform:
Analyte Technology Platform DNA Real-time qPCR Protein Clinical chemistry/auto analyzer Cell count/volume Hematology/ auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Diagnosis/ patient condition NSCLC
Healthy
Preaquisition Prognostic factor Stage I+II
Stage III
Stage IV
Remission/No change
Progression
Real-time qPCR Specific Targeted nucleic acid GAPDH
Biospecimen Acquisition Type of collection container/solution Monovette
Vacutainer
Biospecimen Aliquots and Components Blood and blood products Plasma
Serum
Preaquisition Biomarker level 200-950 U/L LDH
1.75-20 G/L leukocytes