Effect of Vancomycin or Daptomycin With vs Without an Antistaphylococcal ß-Lactam on Mortality, Bacteremia, Relapse, or Treatment Failure in Patients With MRSA Bacteremia: A Randomized Clinical Trial.

Importance: Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with mortality of more than 20%. Combining standard therapy with a ß-lactam antibiotic has been associated with reduced mortality, although adequately powered randomized clinical trials of this intervention have not been conducted. Objective: To determine whether combining an antistaphylococcal ß-lactam with standard therapy is more effective than standard therapy alone in patients with MRSA bacteremia. Design, Setting, and Participants: Open-label, randomized clinical trial conducted at 27 hospital sites in 4 countries from August 2015 to July 2018 among 352 hospitalized adults with MRSA bacteremia. Follow-up was complete on October 23, 2018. Interventions: Participants were randomized to standard therapy (intravenous vancomycin or daptomycin) plus an antistaphylococcal ß-lactam (intravenous flucloxacillin, cloxacillin, or cefazolin) (n = 174) or standard therapy alone (n = 178). Total duration of therapy was determined by treating clinicians and the ß-lactam was administered for 7 days. Main Outcomes and Measures: The primary end point was a 90-day composite of mortality, persistent bacteremia at day 5, microbiological relapse, and microbiological treatment failure. Secondary outcomes included mortality at days 14, 42, and 90; persistent bacteremia at days 2 and 5; acute kidney injury (AKI); microbiological relapse; microbiological treatment failure; and duration of intravenous antibiotics. Results: The data and safety monitoring board recommended early termination of the study prior to enrollment of 440 patients because of safety. Among 352 patients randomized (mean age, 62.2 [SD, 17.7] years; 121 women [34.4%]), 345 (98%) completed the trial. The primary end point was met by 59 (35%) with combination therapy and 68 (39%) with standard therapy (absolute difference, -4.2%; 95% CI, -14.3% to 6.0%). Seven of 9 prespecified secondary end points showed no significant difference. For the combination therapy vs standard therapy groups, all-cause 90-day mortality occurred in 35 (21%) vs 28 (16%) (difference, 4.5%; 95% CI, -3.7% to 12.7%); persistent bacteremia at day 5 was observed in 19 of 166 (11%) vs 35 of 172 (20%) (difference, -8.9%; 95% CI, -16.6% to -1.2%); and, excluding patients receiving dialysis at baseline, AKI occurred in 34 of 145 (23%) vs 9 of 145 (6%) (difference, 17.2%; 95% CI, 9.3%-25.2%). Conclusions and Relevance: Among patients with MRSA bacteremia, addition of an antistaphylococcal ß-lactam to standard antibiotic therapy with vancomycin or daptomycin did not result in significant improvement in the primary composite end point of mortality, persistent bacteremia, relapse, or treatment failure. Early trial termination for safety concerns and the possibility that the study was underpowered to detect clinically important differences in favor of the intervention should be considered when interpreting the findings. Trial Registration: ClinicalTrials.gov Identifier: NCT02365493.

Maf1 is a novel target of PTEN and PI3K signaling that negatively regulates oncogenesis and lipid metabolism.

Maf1 was initially identified as a transcriptional repressor of RNA pol III-transcribed genes, yet little is known about its other potential target genes or its biological function. Here, we show that Maf1 is a key downstream target of PTEN that drives both its tumor suppressor and metabolic functions. Maf1 expression is diminished with loss of PTEN in both mouse models and human cancers. Consistent with its role as a tumor suppressor, Maf1 reduces anchorage-independent growth and tumor formation in mice. PTEN-mediated changes in Maf1 expression are mediated by PTEN acting on PI3K/AKT/FoxO1 signaling, revealing a new pathway that regulates RNA pol III-dependent genes. This regulatory event is biologically relevant as diet-induced PI3K activation reduces Maf1 expression in mouse liver. We further identify lipogenic enzymes as a new class of Maf1-regulated genes whereby Maf1 occupancy at the FASN promoter opposes SREBP1c-mediated transcription activation. Consistent with these findings, Maf1 inhibits intracellular lipid accumulation and increasing Maf1 expression in mouse liver abrogates diet-mediated induction of lipogenic enzymes and triglycerides. Together, these results establish a new biological role for Maf1 as a downstream effector of PTEN/PI3K signaling and reveal that Maf1 is a key element by which this pathway co-regulates lipid metabolism and oncogenesis.

Risk Factors for Nephrotoxicity in Methicillin-Resistant Staphylococcus aureus Bacteraemia: A Post Hoc Analysis of the CAMERA2 Trial.

BACKGROUND: Clinical risk factors for nephrotoxicity in Staphylococcus aureus bacteraemia remain largely undetermined, despite its common occurrence and clinical significance. In an international, multicentre, prospective clinical trial (CAMERA2), which compared standard therapy (vancomycin monotherapy) to combination therapy (adding an anti-staphylococcal beta-lactam) for methicillin-resistant S. aureus bacteraemia, significantly more people in the combination therapy arm experienced acute kidney injury compared with those in the monotherapy arm (23% vs 6%). OBJECTIVE: The aim of this post hoc analysis was to explore in greater depth the risk factors for acute kidney injury from the CAMERA2 trial. METHODS: Among participants of the CAMERA2 trial, demographic-related, infection-related and treatment-related risk factors were assessed for their relationship with acute kidney injury by univariable and multivariable logistic regression. Acute kidney injury was defined by a modified-KDIGO (Kidney Disease: Improving Global Outcomes) criteria (not including urinary output). RESULTS: Of the 266 participants included, age (p = 0.04), randomisation to combination therapy (p = 0.002), vancomycin area under the concentration-time curve (p = 0.03) and receipt of (flu)cloxacillin as the companion beta-lactam (p < 0.001) were significantly associated with acute kidney injury. On a multivariable analysis, concurrent use of (flu)cloxacillin increased the risk of acute kidney injury over four times compared with the use of cefazolin or no beta-lactam. The association of vancomycin area under the concentration-time curve with acute kidney injury also persisted in the multivariable model. CONCLUSIONS: For participants receiving vancomycin for S. aureus bacteraemia, use of (flu)cloxacillin and increased vancomycin area under the concentration-time curve were risk factors for acute kidney injury. These represent potentially modifiable risk factors for nephrotoxicity and highlight the importance of avoiding the use of concurrent nephrotoxins.

Barriers and opportunities for evidence-based health service planning: the example of developing a Decision Analytic Model to plan services for sexually transmitted infections in the UK.

BACKGROUND: Decision Analytic Models (DAMs) are established means of evidence-synthesis to differentiate between health interventions. They have mainly been used to inform clinical decisions and health technology assessment at the national level, yet could also inform local health service planning. For this, a DAM must take into account the needs of the local population, but also the needs of those planning its services. Drawing on our experiences from stakeholder consultations, where we presented the potential utility of a DAM for planning local health services for sexually transmitted infections (STIs) in the UK, and the evidence it could use to inform decisions regarding different combinations of service provision, in terms of their costs, cost-effectiveness, and public health outcomes, we discuss the barriers perceived by stakeholders to the use of DAMs to inform service planning for local populations, including (1) a tension between individual and population perspectives; (2) reductionism; and (3) a lack of transparency regarding models, their assumptions, and the motivations of those generating models. DISCUSSION: Technological advances, including improvements in computing capability, are facilitating the development and use of models such as DAMs for health service planning. However, given the current scepticism among many stakeholders, encouraging informed critique and promoting trust in models to aid health service planning is vital, for example by making available and explicit the methods and assumptions underlying each model, associated limitations, and the process of validation. This can be achieved by consultation and training with the intended users, and by allowing access to the workings of the models, and their underlying assumptions (e.g. via the internet), to show how they actually work. SUMMARY: Constructive discussion and education will help build a consensus on the purposes of STI services, the need for service planning to be evidence-based, and the potential for mathematical tools like DAMs to facilitate this.

Genomics-informed responses in the elimination of COVID-19 in Victoria, Australia: an observational, genomic epidemiological study.

BACKGROUND: A cornerstone of Australia's ability to control COVID-19 has been effective border control with an extensive supervised quarantine programme. However, a rapid recrudescence of COVID-19 was observed in the state of Victoria in June, 2020. We aim to describe the genomic findings that located the source of this second wave and show the role of genomic epidemiology in the successful elimination of COVID-19 for a second time in Australia. METHODS: In this observational, genomic epidemiological study, we did genomic sequencing of all laboratory-confirmed cases of COVID-19 diagnosed in Victoria, Australia between Jan 25, 2020, and Jan 31, 2021. We did phylogenetic analyses, genomic cluster discovery, and integrated results with epidemiological data (detailed information on demographics, risk factors, and exposure) collected via interview by the Victorian Government Department of Health. Genomic transmission networks were used to group multiple genomic clusters when epidemiological and genomic data suggested they arose from a single importation event and diversified within Victoria. To identify transmission of emergent lineages between Victoria and other states or territories in Australia, all publicly available SARS-CoV-2 sequences uploaded before Feb 11, 2021, were obtained from the national sequence sharing programme AusTrakka, and epidemiological data were obtained from the submitting laboratories. We did phylodynamic analyses to estimate the growth rate, doubling time, and number of days from the first local infection to the collection of the first sequenced genome for the dominant local cluster, and compared our growth estimates to previously published estimates from a similar growth phase of lineage B.1.1.7 (also known as the Alpha variant) in the UK. FINDINGS: Between Jan 25, 2020, and Jan 31, 2021, there were 20 451 laboratory-confirmed cases of COVID-19 in Victoria, Australia, of which 15 431 were submitted for sequencing, and 11 711 met all quality control metrics and were included in our analysis. We identified 595 genomic clusters, with a median of five cases per cluster (IQR 2-11). Overall, samples from 11 503 (98·2%) of 11 711 cases clustered with another sample in Victoria, either within a genomic cluster or transmission network. Genomic analysis revealed that 10 426 cases, including 10 416 (98·4%) of 10 584 locally acquired cases, diagnosed during the second wave (between June and October, 2020) were derived from a single incursion from hotel quarantine, with the outbreak lineage (transmission network G, lineage D.2) rapidly detected in other Australian states and territories. Phylodynamic analyses indicated that the epidemic growth rate of the outbreak lineage in Victoria during the initial growth phase (samples collected between June 4 and July 9, 2020; 47·4 putative transmission events, per branch, per year [1/years; 95% credible interval 26·0-85·0]), was similar to that of other reported variants, such as B.1.1.7 in the UK (mean approximately 71·5 1/years). Strict interventions were implemented, and the outbreak lineage has not been detected in Australia since Oct 29, 2020. Subsequent cases represented independent international or interstate introductions, with limited local spread. INTERPRETATION: Our study highlights how rapid escalation of clonal outbreaks can occur from a single incursion. However, strict quarantine measures and decisive public health responses to emergent cases are effective, even with high epidemic growth rates. Real-time genomic surveillance can alter the way in which public health agencies view and respond to COVID-19 outbreaks. FUNDING: The Victorian Government, the National Health and Medical Research Council Australia, and the Medical Research Future Fund.

The implementation of chlamydia screening: a cross-sectional study in the south east of England.

BACKGROUND: England's National Chlamydia Screening Programme (NCSP) provides opportunistic testing for under 25 year-olds in healthcare and non-healthcare settings. The authors aimed to explore relationships between coverage and positivity in relation to demographic characteristics or setting, in order to inform efficient and sustainable implementation of the NCSP. METHODS: The authors analysed mapped NCSP testing data from the South East region of England between April 2006 and March 2007 inclusive to population characteristics. Coverage was estimated by sex, demographic characteristics and service characteristics, and variation in positivity by setting and population group. RESULTS: Coverage in females was lower in the least deprived areas compared with the most deprived areas (OR 0.48; 95% CI 0.45 to 0.50). Testing rates were lower in 20-24-year-olds compared with 15-19-year-olds (OR 0.69; 95% CI 0.67 to 0.72 for females and OR 0.67; 95% CI 0.64 to 0.71 for males), but positivity was higher in older males. Females were tested most often in healthcare services, which also identified the most positives. The greatest proportions of male tests were in university (27%) and military (19%) settings which only identified a total of 11% and 13% of total male positives respectively. More chlamydia-positive males were identified through healthcare services despite fewer numbers of tests. CONCLUSIONS: Testing of males focused on institutional settings where there is a low yield of positives, and limited capacity for expansion. By contrast, the testing of females, especially in urban environments, was mainly through established healthcare services. Future strategies should prioritise increasing male testing in healthcare settings.

Terminal osteoblast differentiation, mediated by runx2 and p27KIP1, is disrupted in osteosarcoma.

The molecular basis for the inverse relationship between differentiation and tumorigenesis is unknown. The function of runx2, a master regulator of osteoblast differentiation belonging to the runt family of tumor suppressor genes, is consistently disrupted in osteosarcoma cell lines. Ectopic expression of runx2 induces p27KIP1, thereby inhibiting the activity of S-phase cyclin complexes and leading to the dephosphorylation of the retinoblastoma tumor suppressor protein (pRb) and a G1 cell cycle arrest. Runx2 physically interacts with the hypophosphorylated form of pRb, a known coactivator of runx2, thereby completing a feed-forward loop in which progressive cell cycle exit promotes increased expression of the osteoblast phenotype. Loss of p27KIP1 perturbs transient and terminal cell cycle exit in osteoblasts. Consistent with the incompatibility of malignant transformation and permanent cell cycle exit, loss of p27KIP1 expression correlates with dedifferentiation in high-grade human osteosarcomas. Physiologic coupling of osteoblast differentiation to cell cycle withdrawal is mediated through runx2 and p27KIP1, and these processes are disrupted in osteosarcoma.

Statistical Process Control Charts for Monitoring Staphylococcus aureus Bloodstream Infections in Australian Health Care Facilities.

BACKGROUND: Staphylococcus aureus bloodstream infection (SAB) in health care settings contributes significantly to mortality, and improved processes are associated with reduced burden of infection. In Australia, health care-associated SAB (HA-SAB) rates are reported as a health care performance indicator, but standardized methods for analyzing longitudinal data are not applied. Our objective was to evaluate the utility of statistical process control chart methodology for reporting HA-SAB and flagging higher than expected rates. METHODS: A real-world test data set was defined as HA-SAB surveillance data collected by 155 Australian health care facilities between June 1, 2015, and June 30, 2017. This included 788 HA-SAB events, corresponding to an overall rate of 0.7 HA-SAB events per 10 000 occupied bed-days. The u-chart was selected as an appropriate tool, given the need for reporting natural units (HA-SAB rates) to a range of stakeholders. Facility-level data were plotted as u-charts, applying warning and control limits (2- and 3-SD thresholds, respectively). RESULTS: Sixty-eight of the 155 participating facilities (43.9%) observed at least 1 HA-SAB event during the studied period. Using the traditional method of Poisson modeling, 56 of these 68 facilities demonstrated overdispersion with variance-to-mean ratio spanning 1.03 to 42.82. Modeling by negative binomial (NB) distribution was therefore applied to enhance functionality. CONCLUSION: The u-chart is an accessible method for monitoring HA-SAB, interpretable by a range of stakeholders. We demonstrate the benefit of NB modeling to account for overdispersion, providing an effective tool to avoid inappropriate flags while maintaining early detection of out-of-control systems throughout a wide range of health care settings.

Increased expression of TATA-binding protein, the central transcription factor, can contribute to oncogenesis.

Despite the central role of TATA-binding protein (TBP) in transcription, changes in cellular TBP concentration produce selective effects on gene expression. Moreover, TBP is up-regulated by oncogenic signaling pathways. These findings suggest that TBP could be a nexus in pathways that regulate cell proliferation and that genetic lesions that result in cellular transformation may produce their effects at least in part through TBP. We provide evidence consistent with this hypothesis, demonstrating that increases in TBP expression contribute to cellular transformation. A Ras-mediated increase in TBP expression is required for full Ras transforming activity. TBP overexpression induces cells to grow in an anchorage-independent manner and to form tumors in athymic mice. These effects on cellular transformation require changes in RNA polymerase II-dependent transcription and on the selective recruitment of TBP to promoters via its DNA binding activity. TBP expression is elevated in human colon carcinomas relative to normal colon epithelium. Both Ras-dependent and Ras-independent mechanisms mediate increases in TBP expression in colon carcinoma cell lines. We conclude that TBP may be a critical component in dysregulated signaling that occurs downstream of genetic lesions that cause tumors.

Genetic and epigenetic analysis of CHEK2 in sporadic breast, colon, and ovarian cancers.

PURPOSE: Germ-line variants in CHEK2 have been associated with increased breast, thyroid, prostate, kidney, and colorectal cancer risk; however, the prevalence of somatic inactivation of CHEK2 in common cancer types is less clear. The aim of this study was to determine if somatic mutation and/or epigenetic modification play a role in development of sporadic breast, colon, or ovarian cancers. EXPERIMENTAL DESIGN: We undertook combined genetic and epigenetic analysis of CHEK2 in sporadic primary breast, ovarian, and colon tumors [all exhibiting chromosome 22q loss of heterozygosity (LOH)] and cancer cell lines. Expression of Chk2 was assessed by immunohistochemistry in 119 ovarian tumors. RESULTS: Two novel germ-line variants were identified; however, none of the primary tumors harbored somatic mutations. Two CpG clusters previously implicated in CHEK2 silencing were investigated for evidence of hypermethylation. No methylation was detected at the distal CpG island. The proximal CpG cluster was methylated in all tumor and normal DNA, suggesting that this might not represent a true CpG island and is not relevant in the control of CHEK2 expression. Twenty-three percent of ovarian tumors were negative for Chk2 protein by immunohistochemistry, but there was no significant correlation between LOH across the CHEK2 locus and intensity of Chk2 staining (P = 0.12). CONCLUSIONS: LOH across the CHEK2 locus is common in sporadic breast, ovarian, and colorectal cancers, but point mutation or epigenetic inactivation of the retained allele is uncommon. Loss of Chk2 protein in ovarian cancer was not associated with allelic status, suggesting that inactivation does not occur as a consequence of haploinsufficiency.

Elevated TATA-binding protein expression drives vascular endothelial growth factor expression in colon cancer.

The TATA-binding protein (TBP) plays a central role in eukaryotic gene transcription. Given its key function in transcription initiation, TBP was initially thought to be an invariant protein. However, studies showed that TBP expression is upregulated by oncogenic signaling pathways. Furthermore, depending on the cell type, small increases in cellular TBP amounts can induce changes in cellular growth properties towards a transformed phenotype. Here we sought to identify the specific TBP-regulated gene targets that drive its ability to induce tumorigenesis. Using microarray analysis, our results reveal that increases in cellular TBP concentrations produce selective alterations in gene expression that include an enrichment for genes involved in angiogenesis. Accordingly, we find that TBP levels modulate VEGFA expression, the master regulator of angiogenesis. Increases in cellular TBP amounts induce VEGFA expression and secretion to enhance cell migration and tumor vascularization. TBP mediates changes in VEGFA transcription requiring its recruitment at a hypoxia-insensitive proximal TSS, revealing a mechanism for VEGF regulation under non-stress conditions. The results are clinically relevant as TBP expression is significantly increased in both colon adenocarcinomas as well as adenomas relative to normal tissue. Furthermore, TBP expression is positively correlated with VEGFA expression. Collectively, these studies support the idea that increases in TBP expression contribute to enhanced VEGFA transcription early in colorectal cancer development to drive tumorigenesis.

Loss of heterozygosity analysis in ductal lavage samples from BRCA1 and BRCA2 carriers: a cautionary tale.

BACKGROUND: Loss of heterozygosity (LOH) in breast ductal lavage (DL) fluid has been reported to be a potential biomarker of malignant change. Interpretation of LOH is reliant on sufficient quality and quantity of DNA. We investigated LOH of the BRCA1/2 loci in DL samples from BRCA1/2 mutation carriers, while also assessing the effect of DNA quantity. METHODS: DNA yield was estimated using quantitative real-time PCR. Allelic status of DL DNA was determined using fluorescently tagged microsatellite markers with the subject's lymphocytic DNA serving as a control. Samples were scored as consistently heterozygous or as demonstrating LOH if the same result was observed in replicate experiments. Additionally, samples were scored as "discordant LOH" if they initially showed LOH, but in replicate experiments either showed heterozygosity or LOH of the opposite allele. RESULTS: In 11 BRCA1 carriers, 46 ducts were assessable, and 39 ducts from 14 BRCA2 carriers were assessable. LOH was observed in 17% and 18% of ducts from BRCA1 and BRCA2, respectively. Discordant results were seen in 23 BRCA1 (50%) and 15 BRCA2 (38%) samples. DNA yield was significantly greater in samples that were consistently heterozygous than those that were either discordant or showed LOH in replicate experiments for both BRCA1 (P = 0.003) and BRCA2 (P = 0.003). CONCLUSIONS: DNA quantity is highly variable between DL samples, with low yields likely to detrimentally affect the interpretation of LOH. In conclusion, LOH may not be an adequate method to detect the early stages of malignant change in samples obtained via DL.

Infections in Australian Aged-Care Facilities: Evaluating the Impact of Revised McGeer Criteria for Surveillance of Urinary Tract Infections.

Our survey of 112 Australian aged-care facilities demonstrated the prevalence of healthcare-associated infections to be 2.9%. Urinary tract infections (UTIs) defined by McGeer criteria comprised 35% of all clinically defined UTIs. To estimate the infection burden in these facilities where microbiologic testing is not routine, modified surveillance criteria for UTIs are necessary.

Influenza vaccination uptake among Victorian healthcare workers: evaluating the success of a statewide program.

OBJECTIVE: Annual influenza vaccination is recommended for all Australian healthcare workers (HCWs). In 2014, a target vaccination uptake of 75% was set for Victorian healthcare facilities. This study aimed to determine the 2014 uptake, describe trends over time and propose an enhanced reporting framework. METHODS: Annual data submitted to the Victorian Healthcare Associated Infection Surveillance System (VICNISS) regarding HCW influenza were evaluated for 2005-2014. Faculty uptake - the number of vaccinations administered divided by total number of staff employed - was reported as a statewide aggregate and stratified by facility size (number of staff employed). RESULTS: In 2014, 78,885 HCWs were vaccinated across 93 healthcare facilities, corresponding to an overall uptake of 72.2%. During 2005-2014, small facilities (<100 HCWs) generally reported highest uptake while larger facilities (≥800 HCWs) recorded lowest uptake. Larger facilities recorded the greatest increase (+13.9%) when 2013 and 2014 seasons were compared. For all healthcare facility size categories, the highest uptake was observed in 2014. CONCLUSION: Influenza vaccination uptake in HCWs has successfully been introduced as a performance indicator in Victorian healthcare facilities and a peak uptake was reported in 2014. Varied trends are evident when uptake is stratified by number of employed HCWs, providing a feasible and meaningful method for benchmarking.

The TATA-binding protein as a regulator of cellular transformation.

The TATA-binding protein, TBP, is used by all three RNA polymerases and is therefore central to the process of gene expression. TBP associates with several subsets of proteins, called TATA-binding protein-associated factors (TAFs). This results in the formation of at least three distinct complexes, SL1, TFIID, and TFIIIB, which dictates whether TBP functions in RNA polymerase (pol) I, pol II, or pol III transcription, respectively. The regulation of gene expression has focused largely on proteins that serve to modulate the efficiency by which the general transcription components, such as TBP, interact with promoters. The possibility of a basal transcription factor, itself, being regulated, and influencing cellular homeostasis, has not been extensively considered. However, recent studies have indicated that TBP is indeed regulated, and that modulation of its cellular concentration has a profound, and surprisingly selective, impact on gene expression that can mediate the normal proliferative responses of cells to growth stimuli as well as the transformation potential of cells.

Gene methylation in breast ductal fluid from BRCA1 and BRCA2 mutation carriers.

PURPOSE: Genomic alterations (including gene hypermethylation) are likely to precede the phenotypic changes associated with breast tumorigenesis. From a prospective collection of ductal lavage (DL) samples from women with a known mutation in BRCA1 or BRCA2, we have assessed promoter methylation with a comparison of results with several variables, including breast cancer (BC) outcome. EXPERIMENTAL DESIGN: Hypermethylation of p16, RASSF1A, twist, and RARbeta was assessed using a qualitative, real-time, nested PCR assay. Associations between methylation status and variables were tested using Fisher's exact test or logistic regression. Analyses were done at three levels: a single breast, a single duct (both over time), and each DL sample in isolation. RESULTS: A total of 168 samples from 93 ducts in 54 breasts have been analyzed in 34 women (16 BRCA1 and 18 BRCA2 mutation carriers). A median of 2 DL was done (range, 1-5), with 7 women developing BC on study, 1 bilateral. Methylation of p16 was associated with a known BRCA1 mutation (P = 0.001, P < 0.001, and P < 0.001 for breast, duct, and sample levels, respectively) and women with a history of contralateral BC (P = 0.001 and P < 0.001 for duct and sample levels, respectively). An association was seen for women who developed BC on study and RASSF1A methylation (P = 0.001 for sample level). CONCLUSIONS: Genetic methylation patterns could potentially be used to predict future BC risk. In addition, p16 methylation may be a predictor of BRCA1 mutation status. Further research is required to corroborate these findings.

Epidermal growth factor receptor 1 (EGFR1) and its variant EGFRvIII regulate TATA-binding protein expression through distinct pathways.

The epidermal growth factor receptor (EGFR) family regulates essential biological processes. Various epithelial tumors are linked to EGFR overexpression or expression of variant forms, such as the EGFR1 variant, EGFRvIII. Perturbations in expression of the transcription initiation factor, TATA-binding protein (TBP), alter cellular growth properties. Here we demonstrate that EGFR1 and EGFRvIII, but not HER2, induce TBP expression at a transcriptional level through distinct mechanisms. EGFR1 enhances the phosphorylation and function of Elk-1, recruiting it to the TBP promoter. In contrast, EGFRvIII robustly induces c-jun expression, stimulating recruitment of c-fos/c-jun to an overlapping AP-1 site. Enhancing c-jun expression alone induces TBP promoter activity through the AP-1 site. To determine the underlying mechanism for differences in Elk-1 function and c-jun expression by these receptors, we inhibited the internalization of EGFR1. Persistent EGFR1 cell surface occupancy mimics EGFRvIII-mediated effects on Elk-1 and c-jun and switches the requirement of Elk-1 to AP-1 for TBP promoter induction. Together, these studies define a new molecular mechanism for the regulation of TBP expression. In addition, we identify distinct molecular targets of EGFR1 and EGFRvIII and demonstrate the importance of receptor internalization in distinguishing their specific functions.