Proceedings of the First Workshop Organized by the IAFSS Working Group on Measurement and Computation of Fire Phenomena (MaCFP)

This paper provides a report of the discussions held at the first workshop on Measurement and Computation of Fire Phenomena (MaCFP) on June 10-11 2017. The first MaCFP work-shop was both a technical meeting for the gas phase subgroup and a planning meeting for the condensed phase subgroup. The gas phase subgroup reported on a first suite of experimental- computational comparisons corresponding to an initial list of target experiments. The initial list of target experiments identifies a series of benchmark configurations with databases deemed suitable for validation of fire models based on a Computational Fluid Dynamics approach. The simulations presented at the first MaCFP workshop feature fine grid resolution at the millimeter- or centimeter- scale: these simulations allow an evaluation of the performance of fire models under high-resolution conditions in which the impact of numerical errors is reduced and many of the discrepancies between experimental data and computational results may be attributed to modeling errors. The experimental-computational comparisons are archived on the MaCFP repository [1]. Furthermore, the condensed phase subgroup presented a review of the main issues associated with measurements and modeling of pyrolysis phenomena. Overall, the first workshop provided an illustration of the potential of MaCFP in providing a response to the general need for greater levels of integration and coordination in fire research, and specifically to the particular needs of model validation.

A systematic review of feeding practices among postoperative patients: is practice in-line with evidenced-based guidelines?

BACKGROUND

Early oral feeding after surgery is best practice among adult, noncritically ill patients. Evidenced-based guidelines (EBG) recommend commencing liquid and solid feeding within 24 h of surgery to improve patient (e.g. reduced morbidity) and hospital (e.g. reduced length of stay) outcomes. Whether these EBG are adhered to in usual clinical practice remains unknown. The present study aimed to identify the time to commencement of first oral feed (liquid or solid) and first solid feed among postoperative, noncritically ill, adult patients.

METHODS

MEDLINE, CINAHL, SCOPUS and Web of Science databases were searched from inception to June 2016 for observational studies reporting liquid and/or solid feeding practices among postoperative patients. Studies reporting a mean/median time to first feed or first solid feed within 24 h of surgery or where ≥75% of patients were feeding by postoperative day one were considered in-line with EBG.

RESULTS

Of 5826 articles retrieved, 29 studies were included. Only 40% and 22% of studies reported time to first feed and time to first solid feed in-line with EBG, respectively. Clear and free liquids were the first diet types commenced in 86% of studies. When solids were commenced, 44% of studies reported using various therapeutic diet types (e.g. light) prior to the commencement of a regular diet. Patients who underwent gastrointestinal procedures appeared more likely to experience delayed postoperative feeding.

CONCLUSIONS

Our findings demonstrate a gap between postoperative feeding evidence and its practical application. This information provides a strong rationale for interventions targeting improved nutritional care following surgery.

Multiple births by a captive swellshark Cephaloscyllium ventriosum via facultative parthenogenesis

Using a novel set of 12 microsatellites, a captive, adult female swellshark Cephaloscyllium ventriosum that produced five pups via parthenogenesis is described; naturally occurring parthenogenesis has been observed in every vertebrate class with the exception of mammals. As demonstrated in this study, a captive environment is ideal for long-term monitoring of animals under controlled conditions, and easily allows the detection of particular facets of their biology.

Discrepancies in central review re-testing of patients with ER-positive and HER2-negative breast cancer in the OPTIMA prelim randomised clinical trial

Background:

There is limited data on results of central re-testing of samples from patients with invasive breast cancer categorised in their local hospital laboratories as oestrogen receptor (ER) positive and human epidermal growth factor receptor homologue 2 (HER2) negative.

Methods:

The Optimal Personalised Treatment of early breast cancer usIng Multiparameter Analysis preliminary study (OPTIMA prelim) was the feasibility phase of a randomised controlled trial to validate the use of multiparameter assay-directed chemotherapy decisions in the UK National Health Service (NHS). Eligibility criteria included ER positivity and HER2 negativity. Central re-testing of receptor status was mandatory.

Results:

Of the 431 patients tested centrally, discrepant results between central and local laboratory results were identified in only 19 (4.4% 95% confidence interval 2.5–6.3%) patients (with 21 tumours). On central review, seven patients had cancers that were ER-negative (1.6%) and 13 (3.0%) patients with 15 tumours had HER2-positive disease, including one tumour discrepant for both biomarkers.

Conclusions:

Central re-testing of receptor status of invasive breast cancers in the UK NHS setting shows a high level of reproducibility in categorising tumours as ER-positive and HER2-negative, and raises questions regarding the cost effectiveness and clinical value of central re-testing in this sub-group of breast cancers in this setting.

Mouse Slc4a11 expressed in Xenopus oocytes is an ideally selective H+/OH- conductance pathway that is stimulated by rises in intracellular and extracellular pH

The SLC4A11 gene encodes the bicarbonate-transporter-related protein BTR1, which is mutated in syndromes characterized by vision and hearing loss. Signs of these diseases [congenital hereditary endothelial dystrophy (CHED) and Harboyan syndrome] are evident in mouse models of Slc4a11 disruption. However, the intrinsic activity of Slc4a11 remains controversial, complicating assignment of its (patho)physiological role. Most studies concur that Slc4a11 transports H⁺ (or the thermodynamically equivalent species OH^-) rather than HCO₃^-, but disparities have arisen as to whether the transport is coupled to another species such as Na⁺ or NH₃/NH₄⁺ Here for the first time, we examine the action of mouse Slc4a11 in Xenopus oocytes. We simultaneously monitor changes in intracellular pH, membrane potential, and conductance as we alter extracellular pH, revealing the electrical and chemical driving forces that underlie the observed ion fluxes. We find that mSlc4a11 is an ideally selective H⁺/OH^- conductive pathway, the action of which is uncoupled from the cotransport of any other ion. We also find that the activity of mSlc4a11 is independently enhanced by both extracellular and intracellular alkalinization, suggesting OH^- as the most likely substrate and providing a novel explanation for the apparent NH₃-dependence of Slc4a11-mediated currents reported by others. We suggest that the unique properties of Slc4a11 action underlie its value as a pH regulator in corneal endothelial cells.

Building a New Model of Care for Rapid Breast Radiotherapy Treatment Planning: Evaluation of the Advanced Practice Radiation Therapist in Cavity Delineation

AIMS

Breast radiotherapy treatment is commonly managed by a multidisciplinary team to ensure optimal delivery of care. We sought a new model of care whereby a clinical specialist radiation therapist (CSRT) delineates the cavity target for whole breast radiotherapy treatment planning and the radiation oncologist validates the contour during final plan review. This study evaluated the radiation oncologist's acceptance of these contours and identified characteristics of cavities suitable for CSRT-directed contouring.

MATERIALS AND METHODS

Following specialised breast oncology education and training by the radiation oncologist, the CSRT prospectively delineated cavities in 30 tangential breast radiotherapy cases and consulted the radiation oncologist in 'complex' cases but directed 'non-complex' cases for treatment planning. Changes to CSRT contours were evaluated using the conformity index. Breast density, time since surgery and cavity location, size and visualisation score [CVS: range 1 (no visible cavity) to 5 (homogenous cavity)] were captured.

RESULTS

Of the 30 CSRT delineated cavities contours, the CSRT directed 20 (66.7%) cases for planning without radiation oncology review; 19 were accepted (without changes) by the radiation oncologist upon final plan review and one was changed by the radiation oncologist (conformity index = 0.93) for boost treatment and did not affect the tangential treatment plan. Ten (33.3%) cases, all CVS ≤ 3, were reviewed with the radiation oncologist before planning (conformity index = 0.88 ± 0.12). CVS was inversely correlated with breast density and cavity size (P < 0.01).

CONCLUSIONS

The CSRT delineated cavities appropriate for clinical radiotherapy treatment planning in women with well-visualised cavities, whereas 'complex' cases with dense breast parenchyma, CVS ≤ 3, and/or cases needing boost radiotherapy treatment required review with the radiation oncologist before planning.

A novel mutant Na+ /HCO3- cotransporter NBCe1 in a case of compound-heterozygous inheritance of proximal renal tubular acidosis

KEY POINTS

The inheritance of two defective alleles of SLC4A4, the gene that encodes the widely-expressed electrogenic sodium bicarbonate cotransporter NBCe1, results in the bicarbonate-wasting disease proximal renal tubular acidosis (pRTA). In the present study, we report the first case of compound-heterozygous inheritance of pRTA (p.Arg510His/p.Gln913Arg) in an individual with low blood pH, blindness and neurological signs that resemble transient ischaemic attacks. We employ fluorescence microscopy on non-polarized (human embryonic kidney) and polarized (Madin-Darby canine kidney) renal cell lines and electrophysiology on Xenopus oocytes to characterize the mutant transporters (R510H and Q913R). Both mutant transporters exhibit enhanced intracellular retention in renal cells, an observation that probably explains the HCO₃^- transport deficit in the individual. Both mutants retain a close-to-normal per molecule Na⁺ /HCO₃^- cotransport activity in Xenopus oocytes, suggesting that they are suitable candidates for folding-correction therapy. However, Q913R expression is uniquely associated with a depolarizing, HCO₃^- independent, Cl^- -conductance in oocytes that could have pathological consequences if expressed in the cells of patients.

ABSTRACT

Proximal renal tubular acidosis (pRTA) is a rare, recessively-inherited disease characterized by abnormally acidic blood, blindness, as well as below average height and weight. pRTA is typically associated with homozygous mutation of the solute carrier 4 family gene SLC4A4. SLC4A4 encodes the electrogenic sodium bicarbonate cotransporter NBCe1, a membrane protein that acts to maintain intracellular and plasma pH. We present the first description of a case of compound-heterozygous inheritance of pRTA. The individual has inherited two mutations in NBCe1: p.Arg510His (R510H) and p.Gln913Arg (Q913R), one from each parent. In addition to the usual features of pRTA, the patient exhibits unusual signs, such as muscle spasms and fever. We have recreated these mutant transporters for expression in model systems. We find that both of the mutant proteins exhibit substantial intracellular retention when expressed in mammalian renal cell lines. When expressed in Xenopus oocytes, we find that the R510H and Q913R-mutant NBCe1 molecules exhibit apparently normal Na⁺ /HCO₃^- cotransport activity but that Q913R is associated with an unusual HCO₃^- independent anion-leak. We conclude that a reduced accumulation of NBCe1 protein in the basolateral membrane of proximal-tubule epithelia is the most probable cause of pRTA in this case. We further note that the Q913R-associated anion-leak could itself be pathogenic if expressed in the plasma membrane of mammalian cells, compromising the benefit of strategies aiming to enhance mutant NBCe1 accumulation in the plasma membrane.

OC-11 - Anticoagulation therapy in selected cancer patients at risk of recurrence of venous thromboembolism

INTRODUCTION

Venous thromboembolism (VTE) in cancer patients is an increasingly frequent clinical problem. The overall impact of VTE on cancer patients can be considerable. Targeted patient selection by identifying patients with clinically significant recurrent VTE may have wider health economic benefits whilst reducing patient risk through over-treatment. In the UK, dalteparin is one licensed anticoagulant for the extended treatment and prevention of recurrence of VTE in cancer patients. Rivaroxaban is a highly selective direct Factor Xa inhibitor with oral bioavailability.

AIM

To assess VTE recurrence in selected cancer patients at risk of recurrence of VTE treated with rivaroxaban or dalteparin. The secondary objectives include safety, acceptability, biomarker identification and health economics.

MATERIALS AND METHODS

Select-d is a prospective, randomised, open label, multicentre pilot trial comparing dalteparin (200 IU/kg daily subcutaneously for 1 month and 150 IU/kg months 2-6); and rivaroxaban (15mg orally twice daily for 3 weeks and 20mg once daily for 6 months in total) for cancer patients with VTE - symptomatic and incidental pulmonary embolism (P)E or symptomatic lower limb proximal deep vein thrombosis (DVT) - with a second placebo-controlled randomisation (rivaroxaban vs placebo) comparing the duration of therapy (6 vs 12 months) in all patients with PE and those with a DVT who are residual vein thrombosis (RVT) positive. 70% of DVT patients are estimated to be RVT positive after initial treatment. 530 patients are being recruited toprovide reliable estimates of the primary outcome (VTE recurrence rates) to within the 95% confidence interval of 8% assuming VTE rates are 10% at six months.

RESULTS

As of 1st December 2015, 264 patients have been recruited from 61 open sites across the UK. Preliminary data indicate that the majority of patients presented with solid tumours (98%), ranging from early or locally advanced (41%) to metastatic disease (57%), and primarily comprising colorectal, lung, and breast malignancies. Only a small number of select-d patients presented with haematological malignancies (2%), which included; leukaemia, myeloma and lymphoma. Over half of the select-d patients had an incidental PE (54%); the remainder had symptomatic PE or DVT (46%). The median number of hours on anticoagulation prior to starting select-d randomised treatment was 48 hours.

CONCLUSIONS

select-d is the first randomised trial for treatment of VTE, investigating the direct oral anticoagulants vs a low molecular weight heparin in patients with cancer. The results will support optimal treatment for this key patient group and are eagerly awaited.

NerveCheck: An inexpensive quantitative sensory testing device for patients with diabetic neuropathy

AIMS

Sensory neuropathy is central to the development of painful neuropathy, and foot ulceration in patients with diabetes. Currently, available QST devices take considerable time to perform and are expensive. NerveCheck is the first inexpensive ($500), portable QST device to perform both vibration and thermal testing and hence evaluate diabetic peripheral neuropathy (DPN). This study was undertaken to establish the reproducibility and diagnostic validity of NerveCheck for detecting neuropathy.

METHODS

130 subjects (28 with DPN, 46 without DPN and 56 control subjects) underwent QST assessment with NerveCheck; vibration perception and thermal testing. DPN was defined according to the Toronto criteria.

RESULTS

NerveCheck's intra correlation coefficient for vibration, cold and warm sensation testing was 0.79 (95% LOA: -4.20 to 6.60), 0.86 (95% LOA: -1.38 to 2.72) and 0.71 (95% LOA: -2.36 to 3.83), respectively. The diagnostic accuracy (AUC) for vibration, cold and warm sensation testing was 86% (SE: 0.038, 95% CI 0.79-0.94), 79% (SE: 0.058, 95% CI 0.68-0.91) and 72% (SE: 0.058, 95% CI 0.60-0.83), respectively.

CONCLUSIONS

This study shows that NerveCheck has good reproducibility and comparable diagnostic accuracy to established QST equipment for the diagnosis of DPN.

Abstract OT3-02-12: OPTIMA (optimal personalised treatment of early breast cancer usIng multi-parameter analysis), a prospective trial to validate the predictive utility and cost-effectiveness of gene expression test-directed chemotherapy decisions

Background: Multi-parameter gene expression assays (MPAs) are widely used to estimate individual patient residual risk and to guide chemotherapy use in hormone-sensitive HER2-negative node-negative early breast cancer. These uses of MPAs have not yet been prospectively validated. OPTIMA aims to validate the use of MPA testing to predict chemotherapy sensitivity in a largely node-positive breast cancer population.

Methods: OPTIMA is a partially blinded multi-center, phase 3 randomized controlled trial with an adaptive two-stage design. The preliminary phase (OPTIMA prelim) evaluated the performance of MPAs to identify a suitable test(s) to be used in the main efficacy trial and assessed the feasibility and acceptability of a large UK trial. Eligible patients are men or women aged 40 years or older who have surgically resected early stage breast cancer, which is ER-positive and HER2-negative and who have either 1-9 involved axillary lymph nodes or tumors of at least 30mm diameter. Randomization is to standard management (chemotherapy followed by endocrine therapy) or to MPA-directed treatment. Those with a tumor categorized as "high-risk" by the test will be assigned to standard management whilst those at "low-risk" will be treated with endocrine therapy alone. OPTIMA prelim used Oncotype DX as the primary discriminator; the main trial will use Prosigna (PAM50). The co-primary outcomes are (1) Invasive Disease Free Survival (IDFS) and (2) cost-effectiveness of test-directed therapy compared to standard practice. Secondary outcomes include IDFS in "low-risk" patients, distant disease free survival, breast cancer specific survival, overall survival and quality of life. An integrated qualitative recruitment study will identify and address challenges to recruitment and informed consent. Tumor blocks from all consenting participants will be banked allowing the performance of alternative MPA technologies to be evaluated. Recruitment of 4500 patients over 4 years will permit demonstration of 3% non-inferiority of test-directed treatment, with 5% significance and 85% power, assuming 3 years follow-up and a control arm 5-year IDFS of at least 85%. The addition of patients from OPTIMA prelim will allow non-inferiority to be assessed with 2.5% significance.

Results: OPTIMA-prelim recruited 412 patients in 23 months from 35 sites. It confirmed the acceptability of randomization to patients with a 47% acceptance rate, and to clinicians and hence the feasibility of a large prospective trial of test-directed treatment running in 100-plus UK sites. It showed that investment into research on test-directed therapy, especially with Prosigna, should be of substantial value to the NHS.

Conclusion: OPTIMA, as one of two large scale prospective trials validating the use of test-guided chemotherapy in node-positive hormone-sensitive early breast cancer will have a global impact on patient treatment. Recruitment into the main efficacy trial will commence in October 2015.

Funding: Project funded by the UK NIHR HTA Programme (10/34/501). Views expressed are those of the authors and not those of the HTA Programme, NIHR, NHS or the DoH.

Citation Format: Stein RC, Marshall A, Hall PS, Bartlett JMS, Rooshenas L, Campbell A, Cameron DA, Rea D, Macpherson I, Earl HM, Poole CJ, Francis A, Morgan A, Harmer V, Pinder SE, Stallard N, Donovan J, Hulme C, McCabe C, Hughes-Davies L, Makris A, Dunn JA. OPTIMA (optimal personalised treatment of early breast cancer usIng multi-parameter analysis), a prospective trial to validate the predictive utility and cost-effectiveness of gene expression test-directed chemotherapy decisions. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-02-12.

The diagnostic accuracy of Neuropad for assessing large and small fibre diabetic neuropathy

AIMS

Neuropad is a simple visual indicator test, with moderate diagnostic performance for diabetic peripheral neuropathy. As it assesses sweating, which is a measure of cholinergic small nerve fibre function, we compared its diagnostic performance against established measures of both large and, more specifically, small fibre damage in patients with diabetes.

METHODS

One hundred and twenty-seven participants (89 without diabetic peripheral neuropathy and 38 with) aged 57 ± 9.7 years underwent assessment with Neuropad, large nerve fibre assessments: Neuropathy Disability Score, vibration perception threshold, peroneal motor nerve conduction velocity; small nerve fibre assessments: neuropathy symptoms (Diabetic Neuropathy Symptoms score) corneal nerve fibre length and warm perception threshold.

RESULTS

Neuropad has a high sensitivity but moderate specificity against large fibre neuropathy assessments: Neuropathy Disability Score (> 2) 70% and 50%, vibration perception threshold (> 14 V) 83% and 53%, and peroneal motor nerve conduction velocity (< 42 m/s) 81% and 54%, respectively. However, the diagnostic accuracy of Neuropad was significantly improved against corneal nerve fibre length (< 14 mm/mm2) with a sensitivity and specificity of 83% and 80%, respectively. Furthermore, the area under the curve for corneal nerve fibre length (85%) was significantly greater than with the Neuropathy Disability Score (66%, P = 0.01) and peroneal motor nerve conduction velocity (70%, P = 0.03). For neuropathic symptoms, sensitivity was 78% and specificity was 60%.

CONCLUSIONS

The data show the improved diagnostic performance of Neuropad against corneal nerve fibre length. This study underlines the importance of Neuropad as a practical diagnostic test for small fibre neuropathy in patients with diabetes.

Radiotracers for molecular imaging of cyclooxygenase-2 (COX-2) enzyme

Cyclooxygenase (COX) enzyme is responsible for the formation of important biological mediators including prostaglandins, prostacyclin and thromboxane to trigger many physiological and patho-physiological responses. COXs exist in two distinct isoforms, a constitutively expressed form (COX-1) and an inducible form (COX-2). COX-2 is involved in the body's response to inflammation and pain. Moreover, it has also been shown that COX-2 is overexpressed in many human cancers, and that COX-2 is involved in various neurodegenerative diseases such as Parkinson's and Alzheimer's disease. COX-2 inhibitors are among the most widely used therapeutics for the treatment of chronic and acute pain and inflammation. Non-invasive monitoring of COX-2 functional expression by means of nuclear molecular imaging techniques like positron emission tomography (PET) and single photon emission computed tomography (SPECT) might provide unique opportunities to obtain data on COX-2 expression levels during disease manifestation and progression to study potential roles of COX-2 under various pathological conditions. The present review summarizes recent research efforts directed to the design and synthesis of radiotracers as molecular probes with special emphasis on COX-2 imaging.

Adaptive designs for clinical trials assessing biomarker-guided treatment strategies

BACKGROUND

The Biomarker Strategy Design has been proposed for trials assessing the value of a biomarker in guiding treatment in oncology. In such trials, patients are randomised to either receive the standard chemotherapy treatment or a biomarker-directed treatment arm, in which biomarker status is used to guide treatment.

METHODS

Motivated by a current trial, we consider an adaptive design in which two biomarkers are assessed. The trial is conducted in two stages. In the first stage, patients in the biomarker-guided arm are assessed using a standard and an alternative cheaper biomarker, with the standard biomarker guiding treatment. An analysis comparing biomarker results is then used to choose the biomarker to use for the remainder of the trial. The new biomarker is used if the results for the two biomarkers are sufficiently similar.

RESULTS

We show that in practical situations the first-stage results can be used to adapt the trial without type I error rate inflation. We also show that there can be considerable cost gains with only a small loss in power in the case where the alternative biomarker is highly concordant with the standard one.

CONCLUSIONS

Adaptive designs have an important role in reducing the cost and increasing the clinical utility of trials evaluating biomarker-guided treatment strategies.

High-peak-power, high-energy, high-average-power pulsed fiber laser system with versatile pulse duration and shape

We present a pulsed fiber laser system with average power up to 265 W, pulse energy up to 10.6 mJ, pulse duration adjustable in the range 500 ps-500 ns, repetition rate fully controllable from single-shot operation up to 1 MHz, and the ability to control peak power independently of pulse energy. The system has a compact, all-spliced construction. Such a versatile laser will have wide applications in materials processing.

Eutectic mixture of local anaesthetics (EMLA) 5% cream as a primary dressing on a painful lower leg ulcer

Patients living with chronic leg ulceration may frequently experience moderate to severe wound-related pain, which may not be alleviated by oral analgesics alone. Poorly controlled leg ulcer pain can prevent timely and effective wound management strategies being implemented, and increase wound healing times. Furthermore, patients with poorly controlled leg ulcer pain can experience continuous pain, which significantly affects quality of life. This case report introduces an innovative way of using the eutectic mixture of local anaesthetics (EMLA) 5% cream to reduce wound-related pain, reduce oral analgesic intake, and improve health-related quality of life for a patient with a painful, chronic lower leg ulcer.

Evaluation of glomerular filtration rate estimation by Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae in oncology patients

BACKGROUND

The aim was to evaluate the accuracy of Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae as a substitute for the gold standard measure of glomerular filtration rate (GFR) using chromium 51 EDTA.

PATIENTS AND METHODS

Retrospective analysis of GFR measurements in oncology patients from a University Teaching Hospital over 3 years was carried out. Bias and precision of estimates of GFR were compared with measured GFR.

RESULTS

Six hundred and sixty patients with measured GFR (median 90 ml/min, range 23-179 ml/min) were identified. Cockcroft-Gault produced the smallest bias (median percentage error -1.4%) and highest precision (median absolute percentage error 14.0%) and was the most accurate for carboplatin dosing. For patients>30% over their ideal body weight (IBW), using IBW+30% in the Cockcroft-Gault formula was more precise than using actual body weight or IBW. The Wright formula was most accurate for patients aged 70+years and patients with a body mass index (BMI)≥30 but overestimated GFR when GFR<50 ml/min.

CONCLUSIONS

When measured GFR is unavailable, we advise estimating GFR using the Cockcroft-Gault formula and using IBW+30% for patients weighing>30% over their IBW. If the GFR is ≥50 ml/min and the patient is >70 years and/or BMI≥30, the Wright formula gives the best estimate of GFR.

Molecular and functional characteristics of ovarian surface epithelial cells transformed by KrasG12D and loss of Pten in a mouse model in vivo

Ovarian cancer is a complex and deadly disease that remains difficult to detect at an early curable stage. Furthermore, although some oncogenic (Kras, Pten/PI3K and Trp53) pathways that are frequently mutated, deleted or amplified in ovarian cancer are known, how these pathways initiate and drive specific morphological phenotypes and tumor outcomes remain unclear. We recently generated Pten(fl/fl); Kras(G12D); Amhr2-Cre mice to disrupt the Pten gene and express a stable mutant form of Kras(G12D) in ovarian surface epithelial (OSE) cells. On the basis of histopathologic criteria, the mutant mice developed low-grade ovarian serous papillary adenocarcinomas at an early age and with 100% penetrance. This highly reproducible phenotype provides the first mouse model in which to study this ovarian cancer subtype. OSE cells isolated from ovaries of mutant mice at 5 and 10 weeks of age exhibit temporal changes in the expression of specific Mullerian epithelial marker genes, grow in soft agar and develop ectopic invasive tumors in recipient mice, indicating that the cells are transformed. Gene profiling identified specific mRNAs and microRNAs differentially expressed in purified OSE cells derived from tumors of the mutant mice compared with wild-type OSE cells. Mapping of transcripts or genes between the mouse OSE mutant data sets, the Kras signature from human cancer cell lines and the human ovarian tumor array data sets, documented significant overlap, indicating that KRAS is a key driver of OSE transformation in this context. Two key hallmarks of the mutant OSE cells in these mice are the elevated expression of the tumor-suppressor Trp53 (p53) and its microRNA target, miR-34a-c. We propose that elevated TRP53 and miR-34a-c may exert negatively regulatory effects that reduce the proliferative potential of OSE cells leading to the low-grade serous adenocarcinoma phenotype.