Joan L. Walker's research while affiliated with University of California and other places

Publications (368)

Article
(Abstracted from Obstet Gynecol 2022;139:157–162) Ovarian cancer represents a disproportionate amount of mortality associated with gynecologic malignancies, with more than 13,940 deaths annually. Two factors that significantly contribute to this are the phenomenon that most women are diagnosed at an advanced stage, and most develop recurrent and ch...
Article
5553 Background: In patients with high-grade ovarian cancer in first-line setting, predictive factors of bevacizumab efficacy are needed, for selecting patients. In ICON-7 trial, a poor tumor intrisic chemosensitivity (defined by unfavorable modeled CA-125 kinetic ELIMination rate constant KELIM) was a predictive biomarker. Among patients with high...
Article
TPS10615 Background: Studies of ovarian cancer screening in the general population have not demonstrated a reduction in ovarian cancer mortality. High-grade pelvic serous carcinomas (HGSCs) have traditionally been thought to originate from the ovarian surface epithelium. However, more recent data strongly suggests that most HGSCs originate from pre...
Article
5501 Background: The Interleukin-6/JAK/STAT3 axis, via an increase in cancer stem-like cell (CSC) survival, is a reported driver of chemotherapy resistance. We hypothesized that addition of the JAK1/2 inhibitor ruxolitinib to standard chemotherapy would be tolerable and, by targeting therapy-resistant cells, improve the progression-free survival (P...
Article
TPS3631 Background: Adenomatous polyps are the acknowledged precursors of colorectal cancer (CRC). Identification and removal of adenomas is the mechanism by which screening is effective in reducing CRC incidence and mortality. Patients with 1-2 non-advanced adenomas ( < 1 cm with neither villous components nor high grade dysplasia) are recommended...
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For evacuations, people must make the critical decision to evacuate or stay followed by a multi-dimensional choice composed of concurrent decisions of their departure time, transportation mode, route, destination, and shelter type. These choices have important impacts on transportation response and evacuation outcomes. While extensive research has...
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Recent technological improvements have expanded the sharing economy (e.g., Airbnb, Lyft, and Uber), coinciding with growing need for evacuation resources. To understand influencers on sharing willingness in evacuations, we employed a multi-modeling approach using three model types: 1) four binary logit models that capture sharing scenario separatel...
Article
Background Racial and ethnic variations in attribution of cervical precancer and cancer to HPV types may result in different HPV vaccine protection, screening test coverage, and clinical management. Methods Pooling data from seven U.S. studies, we calculated the proportional attribution of precancers and cancers to HPV types using HPV DNA typing f...
Article
Background Blocking the PI3K/AKT/mTOR pathway decreases resistance to hormonal therapy in endometrial carcinoma (EC). Objective In this study, the aim was to assess the efficacy and tolerability of everolimus(E)/letrozole (L) or medroxyprogesterone acetate(M)/tamoxifen(T) in the treatment of metastatic EC. Study design This single stage, open-lab...
Article
Objective: To assess the presentation, characteristics, and prognostic significance of symptoms in patients with high-risk early-stage epithelial ovarian cancer. Methods: A retrospective chart review was performed on all patients enrolled in a phase III clinical trial (GOG 157). All patients had surgically staged, high-risk early-stage epithelia...
Article
We estimated travel demand models that incorporate a private autonomous vehicle (AV) option using revealed preference data in which personal chauffeurs simulated a personally owned AV. We investigated four components of activity-based models (ABM): activity pattern and primary destination choice, mode choice, and time of day. We compared the chauff...
Article
The COVID-19 pandemic required employees and businesses across the world to rapidly transition to work from home over extended periods, reaching what is likely the upper bound of telework in many sectors. Past studies have identified both advantages and disadvantages of teleworking. The pandemic experience offers a unique opportunity to examine emp...
Article
Since its inception, the choice modelling field has been dominated by theory-driven modelling approaches. Machine learning offers an alternative data-driven approach for modelling choice behaviour and is increasingly drawing interest in our field. Cross-pollination of machine learning models, techniques and practices could help overcome problems an...
Preprint
Technological advancements are rapidly changing traffic management in cities. Massive adoption of mobile devices and cloud-based applications have created new mechanisms for urban traffic control and management. Specifically, navigation applications have impacted cities in multiple ways by rerouting traffic on their streets. As different routing st...
Article
Background Age and ethnicity are among several factors that influence overall survival (OS) in ovarian cancer. The study objective was to determine whether ethnicity and age were of prognostic significance in women enrolled in a clinical trial evaluating the addition of bevacizumab to front-line therapy. Methods Women with advanced stage ovarian,...
Article
To explore potential travel behavior shifts induced by personally owned, fully autonomous vehicles (AVs), we ran an experiment that provided personal chauffeurs to 43 households in the Sacramento region to simulate life with an AV. Like an advanced AV, the chauffeurs took over driving duties. Households were recruited from the 2018 Sacramento house...
Preprint
BACKGROUND The prevalence of smoking among cervical cancer survivors is strikingly high, yet no smoking cessation interventions to date have specifically targeted this population. This paper describes the study design, methods, and data analysis plans for a randomized clinical trial designed to evaluate the efficacy of a theoretically and empirical...
Article
Background: The prevalence of smoking among cervical cancer survivors is strikingly high, yet no smoking cessation interventions to date have specifically targeted this population. This paper describes the study design, methods, and data analysis plans for a randomized clinical trial designed to evaluate the efficacy of a theoretically and empiric...
Article
Objectives: In a prospective study of platinum-resistant ovarian cancer patients, we examined whether the Disease-related Symptoms-Physical (DRS--P) scale of the NCCN/FACT-Ovarian Cancer Symptom Index-18 (NFOSI-18) is responsive to clinical change in patients estimated by their provider to survive at least six months. Methods: The NFOSI-18, and...
Article
Objectives This surgical window of opportunity (window) study assessed the short-term effect of medroxyprogesterone acetate (MPA) alone vs MPA plus histone deacetylase (HDAC) inhibitor entinostat regulation of progesterone receptor (PR) in women with newly diagnosed endometrioid endometrial adenocarcinoma (EC). Methods A multi-site, randomized, op...
Article
COVID-19 has upended travel across the world, disrupting commute patterns, mode choices, and public transit systems. In the United States, changes to transit service and reductions in passenger volume due to COVID-19 are lasting longer than originally anticipated. In this paper we examine the impacts of the COVID-19 pandemic on individual travel be...
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This paper examines the opportunities for addressing evacuations by leveraging the sharing economy. To support this research, we use a mixed-method approach employing archival research of sharing economy actions, 24 high-ranking expert interviews, and a survey of individuals impacted by Hurricane Irma in 2017 (n = 645). Using these data, we contrib...
Article
5527 Background: Treatment options for patients with recurrent cervical and endometrial cancer remain limited. Even with optimum care, median survival has stalled at 12-17 months. The PARP inhibitor rucaparib has demonstrated activity in both BRCA wild-type and mutant cancers. Furthermore, preclinical studies suggest a synergistic effect of PARP in...
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The COVID-19 pandemic restricted most economic and social activities, impacting travel demand for all transportation modes and especially for transit. We hypothesize that the shifts in travel demand varied by socioeconomic status, and we assess the differential impact of COVID-19 in the Bus Rapid Transit (BRT) patronage across various socioeconomic...
Article
Purpose: This surgical window of opportunity (window) study assessed the short-term effect of medroxyprogesterone acetate (MPA) alone versus MPA plus the histone deacetylase (HDAC) inhibitor entinostat on regulation of progesterone receptor (PR) in women with newly diagnosed endometrioid endometrial adenocarcinoma. Patients and methods: This mul...
Article
Objective To evaluate how women with epithelial ovarian cancer (EOC), dichotomized by BRCA status, tolerate intravenous (IV) or intraperitoneal (IP) chemotherapy given with veliparib and bevacizumab (bev) on a GOG phase I study (GOG 9923, NCT00989651). Methods This is an unplanned, post hoc analysis of an IRB approved, multi-institutional, prospec...
Article
While research on developing and testing automated vehicle (AVs) technologies is well underway, research on their implications on travel-related behavior is in its infancy. The aim of this paper is to summarize and analyze literature that focuses on travel-related behavior impacts of AVs, namely levels 4 and 5, as well as highlight important direct...
Article
Practice changing standardization of lower extremity lymphedema quantitative measurements with integrated patient reported outcomes will likely refine and redefine the optimal risk-reduction strategies to diminish the devastating limb-related dysfunction and morbidity associated with treatment of gynecologic cancers. The National Cancer Institute (...
Article
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Advances in the sharing economy – such as transportation network companies (e.g., Lyft, Uber) and home sharing (e.g., Airbnb) – have coincided with the increasing need for evacuation resources. While peer-to-peer sharing under normal circumstances often suffers from trust barriers, disaster literature indicates that trust and compassion often incre...
Article
Objective To assess quality of life (QOL) in patients who developed lower-extremity lymphedema (LLE) after radical gynecologic cancer surgery on prospective clinical trial GOG 244. Methods The prospective, national, cooperative group trial GOG-0244 determined the incidence of LLE and risk factors for LLE development, as well as associated impacts...
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Submicron particles (∼800 nm) of paclitaxel (SPP) contain 1-2 billion molecules of pure drug that release tumoricidal levels of paclitaxel over many weeks. This study compared two dose-levels of SPP instilled into the peritoneal cavity (IP) in 200 ml of saline post-cytoreductive surgery. Eligible patients with primary (n=6) or recurrent (n=4) epith...
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Regret is often experienced for difficult, important, and accountable choices. Consequently, we hypothesize that random regret minimization (RRM) may better describe evacuation behavior than traditional random utility maximization (RUM). However, in many travel related contexts, such as evacuation departure timing, specifying choice sets can be cha...
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Background: With the advent of primary human papillomavirus testing followed by cytology for cervical cancer screening, visual interpretation of cytology slides remains the last subjective analysis step and suffers from low sensitivity and reproducibility. Methods: We developed a cloud-based whole-slide imaging platform with a deep-learning clas...
Article
e18046 Background: Although advances in chemotherapy, cytoreductive surgery, and maintenance therapy (SOC) improved PFS for high grade epithelial ovarian cancer, > 20% of patients relapse during the first 6 months and 60% relapse after 6 months. Submicron particles (~800 nm) of paclitaxel (SPP) contain 1-2 billion molecules of pure drug that releas...
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HPV35 has been found in only ~2% of invasive cervical cancers (ICC) worldwide but up to 10% in Sub‐Saharan Africa, warranting further investigation and consideration of impact on preventive strategies. We studied HPV35 and race/ethnicity, in relation to the known steps in cervical carcinogenesis, using multiple large epidemiologic studies in the U....
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HPV16 causes half of cervical cancers worldwide; for unknown reasons, most infections resolve within two years. Here, we analyze the viral genomes of 5,328 HPV16-positive case-control samples to investigate mutational signatures and the role of human APOBEC3-induced mutations in viral clearance and cervical carcinogenesis. We identify four de novo...
Article
Identification of high‐risk human papillomavirus genotypes causing cervical precancer is crucial for informing HPV vaccine development and efficacy studies, and for determining which types to include in next‐generation genotyping assays. Co‐occurrence of hrHPV infections is common and complicates carcinogenicity assessment; accurate attribution req...
Article
Objectives: To evaluate the incidence and risk factors for lymphedema associated with surgery for gynecologic malignancies on GOG study 244. Methods: Women undergoing a lymph node dissection for endometrial, cervical, or vulvar cancer were eligible for enrollment. Leg volume was calculated from measurements at 10-cm intervals starting 10 cm abov...
Article
The introduction and adoption of autonomous vehicles (AVs) will likely reshape the transportation system and many economic activities. The economic literature on technology adoption, based on studies in agriculture and other sectors, provides lessons on the diffusion of AVs and its social and economic impacts. We rely on the threshold model of diff...
Article
Background: Secondary surgical cytoreduction in women with platinum-sensitive, recurrent epithelial ovarian, primary peritoneal, or fallopian-tube ("ovarian") cancer is widely practiced but has not been evaluated in phase 3 investigation. Methods: We randomly assigned patients with recurrent ovarian cancer who had received one previous therapy,...
Article
Background: Improvements in disease free survival for epithelial ovarian, peritoneal or fallopian tube cancer (EOC) will only come with improved primary therapy. Incorporation of poly-ADP-ribose inhibitors (PARPi) in the frontline setting may represent one strategy. This study sought to determine the maximum tolerated and feasible doses of the PAR...
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Background: Risk-reducing salpingo-oophorectomy (RRSO) and ovarian cancer screening (OCS) are management options for women at increased risk of ovarian cancer. Long-term effects of these interventions on quality of life (QOL) are not well understood. Methods: GOG-0199 is a prospective cohort study of women at increased ovarian cancer risk who ch...
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Background: Risk-reducing salpingo-oophorectomy (RRSO) has been associated with approximately 50% breast cancer risk reduction among women with a pathogenic variant in BRCA1 or BRCA2 (BRCA1/2), a finding that has recently been questioned. Methods: We estimated incidence rates of breast cancer and all cancers combined during 5 years of follow-up...
Article
Objective: To explore whether patient-reported lymphedema-related symptoms, as measured by the Gynecologic Cancer Lymphedema Questionnaire (GCLQ), are associated with a patient-reported diagnosis of lymphedema of the lower extremity (LLE) and limb volume change (LVC) in patients who have undergone radical surgery, including lymphadenectomy, for en...
Article
Background: Standard treatment of early cervical cancer involves a radical hysterectomy and retroperitoneal lymph node dissection. The existing evidence on the incidence of adverse events following minimally invasive versus open radical hysterectomy for early cervical cancer is either non-randomized or retrospective. Objective: To compare the in...
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An increasing number of papers are focusing on integrating psychological aspects into the typical discrete choice models. The majority of these studies account for several latent effects, but they mainly focused on the direct effect of attitudes, perception, and norms in the discrete choice. None of them consider the effect of intention and its rol...
Article
Background: Human papillomaviruses (HPV) cause over 500 000 cervical cancers each year, most of which occur in low-resource settings. Human papillomavirus genotyping is important to study natural history and vaccine efficacy. We evaluated TypeSeq, a novel, next-generation, sequencing-based assay that detects 51 HPV genotypes, in 2 large internatio...
Article
5523 Background: Veliparib, a poly-(ADP-ribose)-polymerase inhibitor, increases anti-tumor activity when combined with platinum chemotherapy and has monotherapy activity in BRCA deficient tumors. This study was done to determine the recommended phase II dose (RP2D) of veliparib in combination with front line treatment for epithelial ovarian cancer...
Article
Objectives: We investigated the treatment needs and preferences of low socioeconomic status cervical cancer survivors to inform the adaptation of a theoretically- and empirically-based Motivation and Problem-Solving approach to facilitate cessation in this at-risk population. Methods: Individual in-depth interviews were conducted with 12 female smo...
Article
Purpose: To evaluate the impact of two different intraperitoneal (IP) chemotherapy regimens on progression-free survival (PFS) among women with newly diagnosed advanced ovarian carcinoma. Methods: Eligible patients were randomly assigned to six cycles of IV paclitaxel 80 mg/m2 once per week with intravenous (IV) carboplatin area under the curve...
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There have been numerous behavior change studies focused on sustainable travel mode choices. In this study we focused on the residential choices that in turn influence travel habits. We designed and implemented two interventions, which we term the “focalism” and “visualization” interventions, based on literature in psychological economics. The foca...
Article
We have developed a new HPV genotyping assay for detection of 51 HPV genotypes by next generation sequencing (NGS). The TypeSeq assay consists of 3 PCR steps which equalize viral load and each type's amplicon copies prior to genotyping by NGS, thereby maximizing multiple type sensitivity with minimal sequencing reads. The analytical sensitivity of...
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Background: Human papillomavirus (HPV)16 can be separated into genetic sub-lineages (A1-4, B1-4, C1-4, D1-4) which may have differential cervical cancer risk. Methods: A next-generation sequencing assay was used to whole-genome sequence 7116 HPV16-positive cervical samples from well-characterised international epidemiological studies, including...
Technical Report
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In September 2017, Hurricane Irma prompted one of the largest evacuations in U.S. history of over six million people. This mass movement of people, particularly in Florida, required considerable amounts of public resources and infrastructure to ensure the safety of all evacuees in both transportation and sheltering. Given the extent of the disaster...
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Combretastatin A4-phosphate (CA4P) is a vascular-disrupting agent (VDA) in clinical development for the treatment of ovarian and other cancers. In contrast to antiangiogenic agents, such as bevacizumab, which suppress the development of new tumor vasculature, VDAs target established tumor vasculature. These differing but complementary mechanisms of...
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Automated driving technologies are currently penetrating the market, and the coming fully autonomous cars will have far-reaching, yet largely unknown, implications. A critical unknown is the impact on traveler behavior, which in turn impacts sustainability, the economy, and wellbeing. Most behavioral studies, to date, either focus on safety and hum...
Article
Bicycle level of service (LOS) measures are essential tools for transportation agencies to monitor and prioritize improvements to infrastructure for cyclists. While it is apparent that different types of cyclists have varying preferences for the facilities on which they ride, in current research and practice, measures are used that are either insuf...
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Hippo signaling has been recognized as a key tumor suppressor pathway. Here, we perform a comprehensive molecular characterization of 19 Hippo core genes in 9,125 tumor samples across 33 cancer types using multidimensional “omic” data from The Cancer Genome Atlas. We identify somatic drivers among Hippo genes and the related microRNA (miRNA) regula...
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BACKGROUND New cervical cancers continue to be diagnosed despite the success of Papanicolaou (Pap) tests. In an effort to identify pitfalls that limit the diagnosis of adenocarcinoma, the authors reviewed the cytologic characteristics of endocervical adenocarcinomas in their patient population. METHODS Liquid‐based cytology slides from 45 women wh...
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We present an integromic analysis of gene alterations that modulate transforming growth factor β (TGF-β)-Smad-mediated signaling in 9,125 tumor samples across 33 cancer types in The Cancer Genome Atlas (TCGA). Focusing on genes that encode mediators and regulators of TGF-β signaling, we found at least one genomic alteration (mutation, homozygous de...
Article
Background: Black women with endometrial cancer are more likely to die from their disease compared to white women with endometrial cancer. These survival disparities persist even when disproportionately worse tumor characteristics among black women are accounted. Receipt of less complete adjuvant treatment among black endometrial cancer patients c...
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Our comprehensive analysis of alternative splicing across 32 The Cancer Genome Atlas cancer types from 8,705 patients detects alternative splicing events and tumor variants by reanalyzing RNA and whole-exome sequencing data. Tumors have up to 30% more alternative splicing events than normal samples. Association analysis of somatic variants with alt...
Article
Purpose: Bevacizumab (BV) monotherapy leads to compensatory upregulation of multiple signaling pathways, resulting in mTOR activation. We evaluated combining BV and everolimus (EV), an mTOR kinase inhibitor, to circumvent BV-resistance in women with recurrent or persistent ovarian, fallopian tube or primary peritoneal cancer (OC). Patients and me...