] with manual review. Of the cfDNA samples, 6 samples had sufficient tumour purity to estimate copy number aberrations while the remaining 49 had very low tumour purity . The mean purity of these 31 samples was 54% .
In order to increase the power to detect mutations in the cfDNA samples, mutations confidently called in other samples of the same patient were leveraged. However, to reduce the rate of false-positive mutations, multiple thresholds were explored. We reasoned thatmutations in cfDNA samples should tend to be patient-specific, unless they resided in driver mutations. Conversely, artefactual mutations or sequencing noise, are more likely to be recurrent across samples from different patients.
We observed that adopting filters such that a variant read count of 3 or more was required as well as a VAF of greater than 1% or 1.5%, provided a reasonable balance between a high number of likely true positives and a very low estimated number of false positives .In the majority of cfDNA samples , the tumour purity was estimated as lower than 5%, meaning analysis was not possible using ASCAT [].
For each of these minimum consistent genomic regions, the sample with the largest segmentBAF was selected, and all SNPs associated with the segment were classified as belonging to allele A or B based on the individual BAF estimates within that sample being greater or less than 0.5, respectively. The classification of SNPs was then applied to all other samples, including those with no discernible tumour content, in a given patient.
Source: News Formal (newsformal.com)
United Kingdom Latest News, United Kingdom Headlines
Similar News:You can also read news stories similar to this one that we have collected from other news sources.
Source: MENnewsdesk - 🏆 23. / 69 Read more »
Source: medical_xpress - 🏆 101. / 51 Read more »
Source: Glasgow_Times - 🏆 76. / 59 Read more »
Source: SkyNews - 🏆 35. / 67 Read more »
Source: Glasgow_Live - 🏆 4. / 97 Read more »
Source: nottslive - 🏆 96. / 52 Read more »