499431066 曾伊賞

1. Next-Generation Sequencing of Plasma/Serum DNA: An Emerging Research and Molecular Diagnostic Tool 499431066 曾伊賞

2. New Diagnostic Tool • Cell-free DNA and RNA molecules: present in plasma and serum • Detection for : ex: tumor-derived and fetal-derived nucleic acids

3. Clinical Use • In oncology and prenatal diagnosis. • Ex: prenatal determination of fetal RhD status • Ex: detection and monitoring of nasopharyngeal carcinoma (plasma Epstein-Barr virus DNA)

4. Problem • Detecting circulating nucleic acids: conventional cloning and DNA sequencing • Drawback: labor-intensive • New approach: next-generation sequencing

5. Approaches • Two main types: 1. random sequencing of DNA molecules in plasma/serum 2. deep sequencing of a selected subset of circulating DNA molecules

6. 1. Random sequencing of DNA molecules in plasma/serum • used the Illumina/Solexa platform to randomly sequence a short tag on millions of DNA molecules obtained from the plasma of pregnant women.

7. 1. Random sequencing of DNA molecules in plasma/serum • DNA molecules can be mapped back to the reference human genome.

8. 1. Random sequencing of DNA molecules in plasma/serum • Relative representation of each chromosome in plasma showed that in women carrying fetuses affected by a chromosomal aneuploidy (e.g., trisomy 21). • The proportional representation of the affected chromosome (e.g., chromosome 21) would be increased in maternal plasma.

9. 2. Deep sequencing of a selected subset of circulating DNA molecules • Use deep sequencing to perform massively parallel bisulfite sequencing of 4 loci using the Roche/454 platform in sera obtained from cancer patients and control subjects.

10. 2. Deep sequencing of a selected subset of circulating DNA molecules • They found that DNA molecules containing every conceivable cytosine-methylation pattern could be found in the sera of both the cancer patients and cancer-free controls.

11. 2. Deep sequencing of a selected subset of circulating DNA molecules • Thus highlighting the challenge for developing highly specific serum DNA methylation markers for cancer.

12. Conclusion • The bioinformatic support that is needed to analyze the data for most diagnostic laboratories at the present time.

13. Reference • http://www.47project.com/2010/02/05/dna-science-subversion-the-future/ • http://www.123rf.com/photo_3131933_scientist-using-blue-multi-channel-pipet-for-pipetting-a-96-well-plate-with-pink-solution-on-white.html • http://breakthroughblogs.blogspot.tw/2012/04/y-is-for-y-chromosome.html • http://www.istockphoto.com/stock-illustration-11001567-dna-strands.php

14. Thanks for your attention!