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Fetal DNA circulating in maternal plasma and possibilities of its genetic analysis
Soukalová, Adéla ; Korabečná, Marie (advisor) ; Vodička, Radek (referee)
Cell free DNA is short, fragmented DNA found in plasma and serum, into which it is released by various mechanisms. It was first identified in body fluids of cancer patients and soon became a biomarker for non-invasive diagnostics. Soon after, the presence of fetal cfDNA in maternal plasma was detected and became the subject of clinical utility. Non-invasive prenatal diagnosis is a screening method that helps to determine the likelihood of birth defects early in pregnancy, specifically using fetal cfDNA. The final results are determined by invasive methods such as aminocentesis and chorionic villus sampling. Invasive methods of prenatal diagnosis carry a risk of fetal loss of less than 1 %. Despite this low risk, scientists are constantly striving to improve non-invasive methods that can detect aneuploidies such as Down's or Edwards syndrome, as well as determine the sex of the fetus, monogenic diseases and the Rh factor. Polymerase chain reaction (PCR) or next-generation sequencing methods are used for detection.
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Optimization of proces for detection of free tumor DNA in plasma and its clinical utility for colorectal cancer, lung cancer and pancreatic cancer patients
Belšánová, Barbora ; Benešová, Lucie (advisor) ; Tachezy, Ruth (referee)
In current days, examination of circulating tumor DNA (ctDNA) finds new use across different cancers. It is directed at tumor-derived short fragments of DNA present in peripheral blood of patiens (mainly in advanced stages). Due to its minimal invasivity, almost 100 % specificity and relatively high sensitivity in stage IV patients, this approch found its main potential clinical utility especially in early detection of disease relapse or progression after tumor resection (i.e. post-operative follow-up), prediction and monitoring of therapy response and estimation of prognosis. As a result of minute levels of ctDNA on a high background of other non-tumor DNA fragments present in plasma, a suitable method exhibiting highest sensitivity is the key for proper detection of this marker. The approach is predominantly based on initial identification of a mutation in tumor tissue and its subsequent detection in plasma. The present work is aimed at optimization of ctDNA isolation and method of its detection based on PCR amplification followed by heteroduplex analysis by denaturing capillary electrophoresis (DCE) to achieve highest sensitivity for detection of mutated fraction in plasma sample. I have applied the optimized protocol to examine ctDNA in three types of cancers, namely colorectal cancer (122...
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Optimization of proces for detection of free tumor DNA in plasma and its clinical utility for colorectal cancer, lung cancer and pancreatic cancer patients
Belšánová, Barbora ; Benešová, Lucie (advisor) ; Tachezy, Ruth (referee)
In current days, examination of circulating tumor DNA (ctDNA) finds new use across different cancers. It is directed at tumor-derived short fragments of DNA present in peripheral blood of patiens (mainly in advanced stages). Due to its minimal invasivity, almost 100 % specificity and relatively high sensitivity in stage IV patients, this approch found its main potential clinical utility especially in early detection of disease relapse or progression after tumor resection (i.e. post-operative follow-up), prediction and monitoring of therapy response and estimation of prognosis. As a result of minute levels of ctDNA on a high background of other non-tumor DNA fragments present in plasma, a suitable method exhibiting highest sensitivity is the key for proper detection of this marker. The approach is predominantly based on initial identification of a mutation in tumor tissue and its subsequent detection in plasma. The present work is aimed at optimization of ctDNA isolation and method of its detection based on PCR amplification followed by heteroduplex analysis by denaturing capillary electrophoresis (DCE) to achieve highest sensitivity for detection of mutated fraction in plasma sample. I have applied the optimized protocol to examine ctDNA in three types of cancers, namely colorectal cancer (122...
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