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- All Subjects: Bioinformatics
designing personalized treatments and improving clinical outcomes of cancers. Such
investigations require accurate delineation of the subclonal composition of a tumor, which
to date can only be reliably inferred from deep-sequencing data (>300x depth). The
resulting algorithm from the work presented here, incorporates an adaptive error model
into statistical decomposition of mixed populations, which corrects the mean-variance
dependency of sequencing data at the subclonal level and enables accurate subclonal
discovery in tumors sequenced at standard depths (30-50x). Tested on extensive computer
simulations and real-world data, this new method, named model-based adaptive grouping
of subclones (MAGOS), consistently outperforms existing methods on minimum
sequencing depth, decomposition accuracy and computation efficiency. MAGOS supports
subclone analysis using single nucleotide variants and copy number variants from one or
more samples of an individual tumor. GUST algorithm, on the other hand is a novel method
in detecting the cancer type specific driver genes. Combination of MAGOS and GUST
results can provide insights into cancer progression. Applications of MAGOS and GUST
to whole-exome sequencing data of 33 different cancer types’ samples discovered a
significant association between subclonal diversity and their drivers and patient overall
survival.
Evolution has driven organisms to develop a wide range of biological mechanisms to protect against cancer. Some organisms, including the sponge Tethya wilhelma and the Placozoa Trichoplax adhaerens have developed particularly effective mechanisms to suppress cancer and repair DNA damage. While these mechanisms are rooted in DNA damage repair and prevention, evidence of bacteria may suggest that endosymbionts living within the organisms may plays a role as well. Likewise, other organisms, such as the flatworm Macrostomum lignano, are proven model organisms whose extensive documentation enables more in-depth analysis of biological mechanisms associated with cancer. Sponges, flatworms, and Placozoa were exposed to X-ray radiation totaling 600 Gy, 25 Gy, and up to 240 Gy, respectively. RNA sequencing and bioinformatics analyses were undergone to determine the differential gene expression of the animals at different time points. No common response to the X-ray radiation was discovered amongst all organisms. Instead, sponges showed evidence of tumor suppression and DNA repair gene upregulation including CUBN, bacterial endosymbionts showed evidence of lateral gene transfer and different DNA repair genes including FH, and flatworms showed evidence of allelic and mutational shifts in which tumorous populations became more reliant on alternate alleles and a single variant signature. This study highlights the varying mechanisms that have evolved in different organisms and the importance of studying these novel model organisms further.