Abstract
To determine the source of cell‐free DNA detected in the serum of cancer patients, we monitored the release of cell‐free DNA and tumor markers from tumor cell lines using the cell culture technique. During the first 6 days of cell culture, we found very low concentrations of DNA and a steady increase of the CA 125 released from the SK‐BR3 tumor cell lines during cell growth. A sudden increase of cell‐free DNA detected in the cell medium coincided with cell death. As the cells died, the concentration of cell‐free DNA declined but the concentration of CA 125 increased. The sudden release of cell‐free DNA observed upon cell death was also found on the cell cultures of additional tumor cell lines, including A549, RD, and SK‐N‐SH cells. It appears that the majority of cell‐free DNA detected in the serum of cancer patients comes from tumor cells following cell death and cell necrosis. The concentration of cell‐free DNA released is related to the number of dead cells, whereas that of the tumor marker CA 125 is associated with the presence of the total number of cells (dead or alive). J. Clin. Lab. Anal. 17:103–107, 2003. © 2003 Wiley‐Liss, Inc.
Keywords: cell‐free DNA, cell death, necrosis, tissue culture, tumor cell line
REFERENCES
- 1. Jahr S, Hentze H, Englisch S, et al. DNA fragments in the blood plasma of cancer patients: quantitations and evidence for their origin from apoptotic and necrotic cells. Cancer Res 2001;61:1659–1665. [PubMed] [Google Scholar]
- 2. Stroun M, Anker P, Lyautey J, Lederrey C, Maurice PA. Isolation and characterization of DNA from the plasma of cancer patients. Eur J Cancer Clin Oncol 1987;23:707–712. [DOI] [PubMed] [Google Scholar]
- 3. Fournie GJ, Courtin JP, Laval F, et al. Plasma DNA as a marker of cancerous cell death. Investigations in patients suffering from lung cancer and in nude mice bearing human tumours. Cancer Lett 1995;91:221–227. [DOI] [PubMed] [Google Scholar]
- 4. Anker P, Mulcahy H, Chen XQ, Stroun M. Detection of circulating tumour DNA in the blood (plasma/serum) of cancer patients. Cancer Metastasis Rev 1999;18:65–73. [DOI] [PubMed] [Google Scholar]
- 5. Shapiro B, Chakrabarty M, Cohn EM, Leon SA. Determination of circulating DNA levels in patients with benign or malignant gastrointestinal disease. Cancer 1983;51:2116–2120. [DOI] [PubMed] [Google Scholar]
- 6. Wu T‐L, Chia J‐H, Zhang D, Tsao K‐C, Sun C‐F, Wu JT. Cell‐free DNA: measurement in various carcinomas and establishment of normal reference range. Clin Chim Acta 2002;321:77–87. [DOI] [PubMed] [Google Scholar]
- 7. Fournie GJ, Martres F, Pourrat JP, Alary C, Rumeau M. Plasma DNA as cell death marker in elder patients. Gerontology 1993;39:215–221. [DOI] [PubMed] [Google Scholar]
- 8. Fournie GJ, Courtin JP, Chale LF, et al. Plasma DNA as a marker of cancerous cell death. Investigations in patients suffering from lung cancer and in nude mice bearing human tumours. Cancer Lett 1995;91:221–227. [DOI] [PubMed] [Google Scholar]
- 9. Wu JT. c‐erbB2 oncoprotein and its soluble ectodomain: a new potential tumor marker for prognosis, early detection and monitoring patients undergoing Herceptin treatment. Clin Chim Acta 2002;322:11–19. [DOI] [PubMed] [Google Scholar]
- 10. Sjostrom J, Alfthan H, Joensuu H, Stenman UH, Lundin J, Blomqvist C. Serum tumour markers CA 15‐3, TPA, TPS, hCGbeta and TATI in the monitoring of chemotherapy response in metastatic breast cancer. Scand J Clin Lab Invest 2001;61:431–441. [DOI] [PubMed] [Google Scholar]
- 11. Sun C‐F, Haven TR, Wu T‐L, Tsao K‐C, Wu JT. Serum total homocysteine increases with the rapid proliferation rate of tumor cells and decline upon cell death: a potential new tumor marker. Clin Chim Acta 2002;321:55–62. [DOI] [PubMed] [Google Scholar]