Organisms from all domains of life use gene regulation networks to control cell growth, identity, function, and responses to environmental challenges. Although accurate global regulatory models would provide critical evolutionary and functional insights, they remain incomplete, even for the best studied organisms. Efforts to build comprehensive networks are confounded by challenges including network scale, degree of connectivity, complexity of organism–environment interactions, and difficulty of estimating the activity of regulatory factors. Taking advantage of the large number of known regulatory interactions in Bacillus subtilis and two transcriptomics datasets (including one with 38 separate experiments collected specifically for this study), we use a new combination of network component analysis and model selection to simultaneously estimate transcription factor activities and learn a substantially expanded transcriptional regulatory network for this bacterium. In total, we predict 2,258 novel regulatory interactions and recall 74% of the previously known interactions. We obtained experimental support for 391 (out of 635 evaluated) novel regulatory edges (62% accuracy), thus significantly increasing our understanding of various cell processes, such as spore formation.

Women of sub-Saharan African descent have disproportionately higher incidence of Triple Negative Breast Cancer (TNBC), and TNBC-specific mortality. Population comparative studies show racial differences in TNBC biology, including higher prevalence of basal-like and Quadruple-Negative subtypes in African Americans (AA). However, previous investigations relied on self-reported race (SRR) of primarily United States (US) populations. Due to heterogenous genetic admixture, and biological consequences of social determinants, the true association of African ancestry with TNBC biology is unclear. To address this, we conducted RNAseq on an international cohort of AAs, west and east Africans with TNBC. Using comprehensive genetic ancestry estimation in this African-enriched cohort, we found expression of 613 genes associated with African ancestry and 2000+ associated with regional African ancestry. A subset of African-associated genes also showed differences in normal breast tissue. Pathway enrichment and deconvolution of tumor cellular composition revealed tumor-associated immunological profiles are distinct in patients of African descent.

Background: Triple-negative breast cancer (TNBC) remains the most aggressive molecular subtype of breast cancer, with worse survival outcomes compared to other breast cancer subtypes. TNBC prevalence is highest among women of African descent worldwide, and through our previous work we have established a connection between West African ancestry (WAa) and higher rates of TNBC. Specifically, we have shown that prevalence rates of TNBC among West African and African American women are similar and higher than that of East African and White American women. We have also shown that quantified African ancestry is higher among TNBC cases compared to non-TNBC cases. To determine the influence African ancestry on the TNBC tumor environment, we sought to determine any differences in gene expression profiles of Ghanaian (West African) compared to Ethiopian (East African) women. Methods: RNA was extracted and sequenced from a pilot cohort of archival FFPE tumor tissue among Ghanaian (n = 19) and Ethiopian (n = 20) women. RNAseq reads were aligned, and quality of alignments were assessed, where de-duplicated samples with counts above 10M reads were included in the final analysis. Genetic ancestry was quantified by obtaining SNVs called from the RNAseq alignments, using GATK best practices. Differentially expressed genes lists were determined comparing Ghanaian vs. Ethiopian TNBC tumors, and also by identifying genes that were associated with increasing African ancestry. These gene lists, and log-fold change between comparison groups, were used as input for Ingenuity Pathway Analysis (IPA), to identify canonical pathways and de novo networks that are specific to Ghanaian or Ethiopian TNBC tumors. Results: Using 1KG populations as our reference to quantify genetic ancestry, we show that Ghanaian samples have >94% AFR ancestry, specifically matching population groups representative of WAa. The Ethiopian samples showed between 37-48% AFR ancestry, primarily represented by East African groups. Interestingly, there seems to be a significant proportion of EUR ancestry among the Ethiopians samples (30-49%), primarily represented by Italian ancestry. We have conducted the differential gene expression analysis in two ways. First, we have compared gene expression profiles between Ghanaian and Ethiopian tumors. In our preliminary analysis, we identified >600 genes (p < 0.01) that were differentially expressed between Ghanaian and Ethiopian TNBC tumors. Second, we used AFR ancestry as a continuous variable, where we conducted a linear regression analysis to identify genes associated with AFR ancestry. We identified >900 genes associated with AFR ancestry (p < 0.01), and this gene signature distinguished Ghanaian from Ethiopian tumors in an unsupervised hierarchical clustering. In comparing the differentially expressed gene lists from these two approaches, approximately 200 genes were shared, indicating the distinct value of both analyses. Using these gene lists as input for IPA analysis, we have begun to identify canonical pathways that have been altered by our differentially expressed genes, alongside de novo networks that differ between our Ghanaian and Ethiopian tumors. In our overlapping gene list, we see predicted differences in functions such as quantity of T lymphocytes, where genes downregulated in Ethiopian tumors may indicated reduced presence of these immune cells. Using CIBERSORT and xCell deconvolution methods, validation of these findings are ongoing. Conclusions and Ongoing work: This work highlights how ancestry-specific gene regulation can delineate differences in the tumor microenvironment among a cohort of African tumors. We are currently evaluating distribution of TNBC subtypes and estimation of immune cell populations in these tumors, to determine ancestry-specific differences in tumor heterogeneity and immune response. Citation Format: Rachel Martini, Endale Gebregzabher, Princesca Dorsaint, Timothy Chu, Kanika Arora, Lee Gibbs, Zarko Manojlovic, Nicolas Robine, Andrea Sboner, Olivier Elemento, John Carpten, Lisa Newman, Melissa Davis. Gene expression profiles of Ghanaian and Ethiopian triple-negative breast tumors [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SS1-07.

More patients with EtOH withdrawal-related ED visits had a long QTc than patients presenting with ACS. ED physicians should carefully monitor patients experiencing EtOH withdrawal for cardiac arrhythmias and obtain an ECG. If any medications that prolong the QTc are considered, then an ECG should be obtained before administering medications that may affect the myocardium to make medication safer for the patient.

Supplementary Table from African Ancestry–Associated Gene Expression Profiles in Triple-Negative Breast Cancer Underlie Altered Tumor Biology and Clinical Outcome in Women of African Descent