Provided herein are methods and compositions to extract and enrich by, physical separation or amplification, relatively short nucleic acids from a nucleic acid composition containing a high background of longer nucleic acids (e.g., host or maternal nucleic acids; genomic nucleic acid and the like).

Provided herein are methods and compositions to extract and enrich by, physical separation or amplification, relatively short nucleic acids from a nucleic acid composition containing a high background of longer nucleic acids (e.g., host or maternal nucleic acids; genomic nucleic acid and the like).

The present invention describes methods of removing DNA from an RNA transcript during the mRNA production process. The method embodies procedures for obtaining an in vitro transcription product, and removing any DNA from the product. The DNA can be removed by adding either free DNase or a resin containing immobilized DNase to the product, and recovering the RNA transcript. Alternatively, the DNA template used in the in vitro transcription reaction is labeled. After transcription, the product is applied to a resin that is configured to bind the label, and the RNA transcript is recovered. To detect whether any residual impurities are left in the RNA transcript product, the product is subjected to nuclease digestion and subsequently to liquid chromatography-tandem mass spectrometry analysis to quantitate any residual DNA. The present invention demonstrates efficient and effective methods of isolating an RNA transcript from an in vitro transcription product.

The present invention describes methods of removing DNA from an RNA transcript during the mRNA production process. The method embodies procedures for obtaining an in vitro transcription product, and removing any DNA from the product. The DNA can be removed by adding either free DNase or a resin containing immobilized DNase to the product, and recovering the RNA transcript. Alternatively, the DNA template used in the in vitro transcription reaction is labeled. After transcription, the product is applied to a resin that is configured to bind the label, and the RNA transcript is recovered. To detect whether any residual impurities are left in the RNA transcript product, the product is subjected to nuclease digestion and subsequently to liquid chromatography-tandem mass spectrometry analysis to quantitate any residual DNA. The present invention demonstrates efficient and effective methods of isolating an RNA transcript from an in vitro transcription product.

Methods for detection of MSI in a solid tumor without the need of tumor tissue are presented. In especially preferred methods, a blood sample from a patient is used to isolate ctDNA from serum and nuclear DNA from leukocytes. So obtained DNA is then employed as source material for MSI detection, typically via amplification of one or more MSI loci. In especially preferred aspects, size analysis of amplicons is performed without the need for fluorescent markers.

A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.

A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.

The analysis method for extracellular vesicles, according to the present invention, uses the size-specific separation ability of size exclusion chromatography and the properties of a probe that specifically binds with extracellular vesicles, and by using same is capable of the rapid and easy analysis of the quantity of extracellular vesicles included in a sample, analysis of the physicochemical properties of the extracellular vesicles, analysis of the kind and quantity of the components included in the extracellular vesicles, and analysis of the binding properties or affinity of the probe with respect to the components of the extracellular vesicles. In addition, using the analysis method of the present invention not only enables accurate analysis of extracellular vesicles in a sample, without a sample purification or pre-processing step, but also enables accurate and simple analysis of the components of extracellular vesicles, according to the kind of probe, and thus can improve the efficiency of diagnosis using extracellular vesicles. Also, analysis of the properties or affinity of the probe can be applied to, for example, extracellular vesicle-specific antibody screening, protein screening and chemical-substance screening.

The analysis method for extracellular vesicles, according to the present invention, uses the size-specific separation ability of size exclusion chromatography and the properties of a probe that specifically binds with extracellular vesicles, and by using same is capable of the rapid and easy analysis of the quantity of extracellular vesicles included in a sample, analysis of the physicochemical properties of the extracellular vesicles, analysis of the kind and quantity of the components included in the extracellular vesicles, and analysis of the binding properties or affinity of the probe with respect to the components of the extracellular vesicles. In addition, using the analysis method of the present invention not only enables accurate analysis of extracellular vesicles in a sample, without a sample purification or pre-processing step, but also enables accurate and simple analysis of the components of extracellular vesicles, according to the kind of probe, and thus can improve the efficiency of diagnosis using extracellular vesicles. Also, analysis of the properties or affinity of the probe can be applied to, for example, extracellular vesicle-specific antibody screening, protein screening and chemical-substance screening.

A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.