Breaking Discovery: Tissue Biopsies on their way out

No Tissue Biopsy for cancer detection : Simple blood plasma assay (a liquid biopsy) may be the method of cancer detection in future

Blood plasma,  the straw-colored liquid component of blood that normally holds the blood cells in whole blood in suspension contains dissolved proteins, glucose, clotting factors, mineral  ions,  hormones  and carbon dioxide and DNA. Plasma of cancer patients contains cell-free tumor DNA that carries information on tumor mutations and tumor burden. Though individual mutations have been probed earlier, for the first time a method has been  developed  ( by a team of researchers from UK) for tagged-amplicon deep sequencing (TAm-Seq) which resulted in  screening  5995 genomic bases for low-frequency mutations. Using this method they  identified cancer mutations present in circulating DNA at allele frequencies as low as 2%, with sensitivity and specificity of >97%.They identified mutations throughout the tumor 

suppressor gene TP53 in circulating DNA from 46 plasma samples of advanced ovarian cancer patients. They also  demonstrated use of TAm-Seq to noninvasively identify the origin of metastatic relapse in a patient with multiple primary tumors. In another case, they identified in plasma an EGFR mutation not found in an initial ovarian biopsy. They further used TAm-Seq to monitor tumor dynamics, and tracked 10 concomitant mutations in plasma of a metastatic breast cancer patient over 16 months. This low-cost, high-throughput method could facilitate analysis of circulating DNA as a noninvasive “liquid biopsy” for personalized cancer genomics.

[Reproduced from  Future Genomics ]

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