No abstract

We examined mitochondrial DNA (mtDNA) haplogroup and haplotype diversity in 188 individuals from three Chibchan (Kogi, Arsario, and Ijka) populations and one Arawak (Wayuú) group from northeast Colombia to determine the biological relationship between lower Central American and northern South American Chibchan speakers. mtDNA haplogroups were obtained for all individuals and mtDNA HVS-I sequence data were obtained for 110 samples. Resulting sequence data were compared to 16 other Caribbean, South, and Central American populations using diversity measures, neutrality test statistics, sudden and spatial mismatch models, intermatch distributions, phylogenetic networks, and a multidimensional scaling plot. Our results demonstrate the existence of a shared maternal genetic structure between Central American Chibchan, Mayan populations and northern South American Chibchan-speakers. Additionally, these results suggest an expansion of Chibchan-speakers into South America associated with a shift in subsistence strategies because of changing ecological conditions that occurred in the region between 10,000-14,000 years before present.

No abstract

Individual mutations in the tumor suppressor TP53 alter p53 protein function. Some mutations create a non-functional protein, whereas others confer oncogenic activity, which we term ‘oncomorphic’. Since mutations in TP53 occur in nearly all ovarian tumors, the objective of this study was to determine the relationship of oncomorphic TP53 mutations with patient outcomes in advanced serous ovarian cancer patients. Clinical and molecular data from 264 high-grade serous ovarian cancer patients uniformly treated with standard platinum- and taxane-based adjuvant chemotherapy were downloaded from The Cancer Genome Atlas (TCGA) portal. Additionally, patient samples were obtained from the University of Iowa and individual mutations were analyzed in ovarian cancer cell lines. Mutations in the TP53 were annotated and categorized as oncomorphic, loss of function (LOF), or unclassified. Associations between mutation types, chemoresistance, recurrence, and progression-free survival (PFS) were calculated. Oncomorphic TP53 mutations were present in 21.3% of ovarian cancers in the TCGA dataset. Patients with oncomorphic TP53 mutations demonstrated significantly worse PFS, a 60% higher risk of recurrence (HR=1.60, 95% confidence intervals 1.09, 2.33, p=0.015), and higher rates of platinum resistance (χ2 test p=0.0024) when compared with single nucleotide mutations not categorized as oncomorphic. Furthermore, tumors containing oncomorphic TP53 mutations displayed unique protein expression profiles, and some mutations conferred increased clonogenic capacity in ovarian cancer cell models. Our study reveals that oncomorphic TP53 mutations are associated with worse patient outcome. These data suggest that future studies should take into consideration the functional consequences of TP53 mutations when determining treatment options.