Risk Model-Based Lung Cancer Screening : A Cost-Effectiveness Analysis.

BACKGROUND: In their 2021 lung cancer screening recommendation update, the U.S. Preventive Services Task Force (USPSTF) evaluated strategies that select people based on their personal lung cancer risk (risk model-based strategies), highlighting the need for further research on the benefits and harms of risk model-based screening. OBJECTIVE: To evaluate and compare the cost-effectiveness of risk model-based lung cancer screening strategies versus the USPSTF recommendation and to explore optimal risk thresholds. DESIGN: Comparative modeling analysis. DATA SOURCES: National Lung Screening Trial; Surveillance, Epidemiology, and End Results program; U.S. Smoking History Generator. TARGET POPULATION: 1960 U.S. birth cohort. TIME HORIZON: 45 years. PERSPECTIVE: U.S. health care sector. INTERVENTION: Annual low-dose computed tomography in risk model-based strategies that start screening at age 50 or 55 years, stop screening at age 80 years, with 6-year risk thresholds between 0.5% and 2.2% using the PLCOm2012 model. OUTCOME MEASURES: Incremental cost-effectiveness ratio (ICER) and cost-effectiveness efficiency frontier connecting strategies with the highest health benefit at a given cost. RESULTS OF BASE-CASE ANALYSIS: Risk model-based screening strategies were more cost-effective than the USPSTF recommendation and exclusively comprised the cost-effectiveness efficiency frontier. Among the strategies on the efficiency frontier, those with a 6-year risk threshold of 1.2% or greater were cost-effective with an ICER less than $100 000 per quality-adjusted life-year (QALY). Specifically, the strategy with a 1.2% risk threshold had an ICER of $94 659 (model range, $72 639 to $156 774), yielding more QALYs for less cost than the USPSTF recommendation, while having a similar level of screening coverage (person ever-screened 21.7% vs. USPSTF's 22.6%). RESULTS OF SENSITIVITY ANALYSES: Risk model-based strategies were robustly more cost-effective than the 2021 USPSTF recommendation under varying modeling assumptions. LIMITATION: Risk models were restricted to age, sex, and smoking-related risk predictors. CONCLUSION: Risk model-based screening is more cost-effective than the USPSTF recommendation, thus warranting further consideration. PRIMARY FUNDING SOURCE: National Cancer Institute (NCI).

Cost-effectiveness analysis of the 2019 American Society for Colposcopy and Cervical Pathology Risk-Based Management Consensus Guidelines for the management of abnormal cervical cancer screening tests and cancer precursors.

BACKGROUND: The guidelines for managing abnormal cervical cancer screening tests changed from a results-based approach in 2012 to a risk-based approach in 2019. OBJECTIVE: We estimated the cost-effectiveness of the 2019 management guidelines and the changes in resource utilization moving from 2012 to 2019 guidelines. STUDY DESIGN: We utilized a previously published model of cervical cancer natural history and screening to estimate and compare the lifetime costs and the number of screens, colposcopies, precancer treatments, cancer cases, and cancer deaths associated with the 2012 vs 2019 management guidelines. We assessed these guidelines under the scenarios of observed screening practice and perfect screening adherence to 3-year cytology starting at age 21, with a switch to either 3-year or 5-year cytology plus human papillomavirus cotesting at age 30. In addition, we estimated the lifetime costs and life years to determine the cost-effectiveness of shifting to the 2019 management guidelines. RESULTS: Under the assumptions of both observed screening practice and perfect screening adherence with a strategy of 3-year cytology at ages 21 to 29 and switching to 3-year cotesting at age 30, the management of the screening tests according to the 2019 guidelines was less costly and more effective than the 2012 guidelines. For 3-year cytology screening at ages 21 to 29 and switching to 5-year cotesting at age 30, the 2019 guidelines were more cost-effective at a willingness-to-pay threshold of $100,000 per life year gained. Across all scenarios, the 2019 management guidelines were associated with fewer colposcopies and cancer deaths. CONCLUSION: Our model-based analysis suggests that the 2019 guidelines are more effective overall and also more cost-effective than the 2012 guidelines, supporting the principle of "equal management of equal risks."

The impact of overdiagnosis on the selection of efficient lung cancer screening strategies.

The U.S. Preventive Services Task Force (USPSTF) recently updated their national lung screening guidelines and recommended low-dose computed tomography (LDCT) for lung cancer (LC) screening through age 80. However, the risk of overdiagnosis among older populations is a concern. Using four comparative models from the Cancer Intervention and Surveillance Modeling Network, we evaluate the overdiagnosis of the screening program recommended by USPSTF in the U.S. 1950 birth cohort. We estimate the number of LC deaths averted by screening (D) per overdiagnosed case (O), yielding the ratio D/O, to quantify the trade-off between the harms and benefits of LDCT. We analyze 576 hypothetical screening strategies that vary by age, smoking, and screening frequency and evaluate efficient screening strategies that maximize the D/O ratio and other metrics including D and life-years gained (LYG) per overdiagnosed case. The estimated D/O ratio for the USPSTF screening program is 2.85 (model range: 1.5-4.5) in the 1950 birth cohort, implying LDCT can prevent ∼3 LC deaths per overdiagnosed case. This D/O ratio increases by 22% when the program stops screening at an earlier age 75 instead of 80. Efficiency frontier analysis shows that while the most efficient screening strategies that maximize the mortality reduction (D) irrespective of overdiagnosis screen through age 80, screening strategies that stop at age 75 versus 80 produce greater efficiency in increasing life-years gained per overdiagnosed case. Given the risk of overdiagnosis with LC screening, the stopping age of screening merits further consideration when balancing benefits and harms.

Cost-effectiveness of follow-up of pulmonary nodules incidentally detected on cardiac computed tomographic angiography in patients with suspected coronary artery disease.

BACKGROUND: Pulmonary nodules (PNs) are often detected incidentally during coronary computed tomographic (CT) angiography, which is increasingly being used to evaluate patients with chest pain symptoms. However, the efficiency of following up on incidentally detected PN is unknown. METHODS AND RESULTS: We determined demographic and clinical characteristics of stable symptomatic patients referred for coronary CT angiography in whom incidentally detected PNs warranted follow-up. A validated lung cancer simulation model was populated with data from these patients, and clinical and economic consequences of follow-up per Fleischner guidelines versus no follow-up were simulated. Of the 3665 patients referred for coronary CT angiography, 591 (16%) had PNs requiring follow-up. The mean age of patients with PNs was 59±10 years; 66% were male; 67% had ever smoked; and 21% had obstructive coronary artery disease. The projected overall lung cancer incidence was 5.8% in these patients, but the majority died of coronary artery disease (38%) and other causes (57%). Follow-up of PNs was associated with a 4.6% relative reduction in cumulative lung cancer mortality (absolute mortality: follow-up, 4.33% versus non-follow-up, 4.54%), more downstream testing (follow-up, 2.34 CTs per patient versus non-follow-up, 1.01 CTs per patient), and an average increase in quality-adjusted life of 7 days. Costs per quality-adjusted life-year gained were $154 700 to follow up the entire cohort and $129 800 per quality-adjusted life-year when only smokers were included. CONCLUSIONS: Follow-up of PNs incidentally detected in patients undergoing coronary CT angiography for chest pain evaluation is associated with a small reduction in lung cancer mortality. However, significant downstream testing contributes to limited efficiency, as demonstrated by a high cost per quality-adjusted life-year, especially in nonsmokers.

Personalizing annual lung cancer screening for patients with chronic obstructive pulmonary disease: A decision analysis.

BACKGROUND: Lung cancer screening with annual chest computed tomography (CT) is recommended for current and former smokers with a ≥30-pack-year smoking history. Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of developing lung cancer and may benefit from screening at lower pack-year thresholds. METHODS: We used a previously validated simulation model to compare the health benefits of lung cancer screening in current and former smokers ages 55-80 with ≥30 pack-years with hypothetical programs using lower pack-year thresholds for individuals with COPD (≥20, ≥10, and ≥1 pack-years). Calibration targets for COPD prevalence and associated lung cancer risk were derived using the Framingham Offspring Study limited data set. We performed sensitivity analyses to evaluate the stability of results across different rates of adherence to screening, increased competing mortality risk from COPD, and increased surgical ineligibility in individuals with COPD. The primary outcome was projected life expectancy. RESULTS: Programs using lower pack-year thresholds for individuals with COPD yielded the highest life expectancy gains for a given number of screens. Highest life expectancy was achieved when lowering the pack-year threshold to ≥1 pack-year for individuals with COPD, which dominated all other screening strategies. These results were stable across different adherence rates to screening and increases in competing mortality risk for COPD and surgical ineligibility. CONCLUSIONS: Current and former smokers with COPD may disproportionately benefit from lung cancer screening. A lower pack-year threshold for screening eligibility may benefit this high-risk patient population.

Benefits and harms of computed tomography lung cancer screening strategies: a comparative modeling study for the U.S. Preventive Services Task Force.

BACKGROUND: The optimum screening policy for lung cancer is unknown. OBJECTIVE: To identify efficient computed tomography (CT) screening scenarios in which relatively more lung cancer deaths are averted for fewer CT screening examinations. DESIGN: Comparative modeling study using 5 independent models. DATA SOURCES: The National Lung Screening Trial; the Prostate, Lung, Colorectal, and Ovarian Cancer Screening trial; the Surveillance, Epidemiology, and End Results program; and the U.S. Smoking History Generator. TARGET POPULATION: U.S. cohort born in 1950. TIME HORIZON: Cohort followed from ages 45 to 90 years. PERSPECTIVE: Societal. INTERVENTION: 576 scenarios with varying eligibility criteria (age, pack-years of smoking, years since quitting) and screening intervals. OUTCOME MEASURES: Benefits included lung cancer deaths averted or life-years gained. Harms included CT examinations, false-positive results (including those obtained from biopsy/surgery), overdiagnosed cases, and radiation-related deaths. RESULTS OF BEST-CASE SCENARIO: The most advantageous strategy was annual screening from ages 55 through 80 years for ever-smokers with a smoking history of at least 30 pack-years and ex-smokers with less than 15 years since quitting. It would lead to 50% (model ranges, 45% to 54%) of cases of cancer being detected at an early stage (stage I/II), 575 screening examinations per lung cancer death averted, a 14% (range, 8.2% to 23.5%) reduction in lung cancer mortality, 497 lung cancer deaths averted, and 5250 life-years gained per the 100,000-member cohort. Harms would include 67,550 false-positive test results, 910 biopsies or surgeries for benign lesions, and 190 overdiagnosed cases of cancer (3.7% of all cases of lung cancer [model ranges, 1.4% to 8.3%]). RESULTS OF SENSITIVITY ANALYSIS: The number of cancer deaths averted for the scenario varied across models between 177 and 862; the number of overdiagnosed cases of cancer varied between 72 and 426. LIMITATIONS: Scenarios assumed 100% screening adherence. Data derived from trials with short duration were extrapolated to lifetime follow-up. CONCLUSION: Annual CT screening for lung cancer has a favorable benefit-harm ratio for individuals aged 55 through 80 years with 30 or more pack-years' exposure to smoking. PRIMARY FUNDING SOURCE: National Cancer Institute.

Comparative analysis of 5 lung cancer natural history and screening models that reproduce outcomes of the NLST and PLCO trials.

BACKGROUND: The National Lung Screening Trial (NLST) demonstrated that low-dose computed tomography screening is an effective way of reducing lung cancer (LC) mortality. However, optimal screening strategies have not been determined to date and it is uncertain whether lighter smokers than those examined in the NLST may also benefit from screening. To address these questions, it is necessary to first develop LC natural history models that can reproduce NLST outcomes and simulate screening programs at the population level. METHODS: Five independent LC screening models were developed using common inputs and calibration targets derived from the NLST and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO). Imputation of missing information regarding smoking, histology, and stage of disease for a small percentage of individuals and diagnosed LCs in both trials was performed. Models were calibrated to LC incidence, mortality, or both outcomes simultaneously. RESULTS: Initially, all models were calibrated to the NLST and validated against PLCO. Models were found to validate well against individuals in PLCO who would have been eligible for the NLST. However, all models required further calibration to PLCO to adequately capture LC outcomes in PLCO never-smokers and light smokers. Final versions of all models produced incidence and mortality outcomes in the presence and absence of screening that were consistent with both trials. CONCLUSIONS: The authors developed 5 distinct LC screening simulation models based on the evidence in the NLST and PLCO. The results of their analyses demonstrated that the NLST and PLCO have produced consistent results. The resulting models can be important tools to generate additional evidence to determine the effectiveness of lung cancer screening strategies using low-dose computed tomography.

Use of Imputation and Decision Modeling to Improve Diagnosis and Management of Patients at Risk for New-Onset Diabetes After Transplantation.

BACKGROUND New-onset diabetes after transplantation (NODAT) is a complication of solid organ transplantation. We sought to determine the extent to which NODAT goes undiagnosed over the course of 1 year following transplantation, analyze missed or later-diagnosed cases of NODAT due to poor hemoglobin A1c (HbA1c) and fasting blood glucose (FBG) collection, and to estimate the impact that improved NODAT screening metrics may have on long-term outcomes. MATERIAL AND METHODS This was a retrospective study utilizing 3 datasets from a single center on kidney, liver, and heart transplantation patients. Retrospective analysis was supplemented with an imputation procedure to account for missing data and project outcomes under perfect information. In addition, the data were used to inform a simulation model used to estimate life expectancy and cost-effectiveness of a hypothetical intervention. RESULTS Estimates of NODAT incidence increased from 27% to 31% in kidney transplantation patients, from 31% to 40% in liver transplantation patients, and from 45% to 67% in heart transplantation patients, when HbA1c and FBG were assumed to be collected perfectly at all points. Perfect screening for kidney transplantation patients was cost-saving, while perfect screening for liver and heart transplantation patients was cost-effective at a willingness-to-pay threshold of $100 000 per life-year. CONCLUSIONS Improved collection of HbA1c and FBG is a cost-effective method for detecting many additional cases of NODAT within the first year alone. Additional research into both improved glucometric monitoring as well as effective strategies for mitigating NODAT risk will become increasingly important to improve health in this population.

Cost-effectiveness Evaluation of the 2021 US Preventive Services Task Force Recommendation for Lung Cancer Screening.

IMPORTANCE: The US Preventive Services Task Force (USPSTF) issued its 2021 recommendation on lung cancer screening, which lowered the starting age for screening from 55 to 50 years and the minimum cumulative smoking exposure from 30 to 20 pack-years relative to its 2013 recommendation. Although costs are expected to increase because of the expanded screening eligibility criteria, it is unknown whether the new guidelines for lung cancer screening are cost-effective. OBJECTIVE: To evaluate the cost-effectiveness of the 2021 USPSTF recommendation for lung cancer screening compared with the 2013 recommendation and to explore the cost-effectiveness of 6 alternative screening strategies that maintained a minimum cumulative smoking exposure of 20 pack-years and an ending age for screening of 80 years but varied the starting ages for screening (50 or 55 years) and the number of years since smoking cessation (≤15, ≤20, or ≤25). DESIGN, SETTING, AND PARTICIPANTS: A comparative cost-effectiveness analysis using 4 independently developed microsimulation models that shared common inputs to assess the population-level health benefits and costs of the 2021 recommended screening strategy and 6 alternative screening strategies compared with the 2013 recommended screening strategy. The models simulated a 1960 US birth cohort. Simulated individuals entered the study at age 45 years and were followed up until death or age 90 years, corresponding to a study period from January 1, 2005, to December 31, 2050. EXPOSURES: Low-dose computed tomography in lung cancer screening programs with a minimum cumulative smoking exposure of 20 pack-years. MAIN OUTCOMES AND MEASURES: Incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) of the 2021 vs 2013 USPSTF lung cancer screening recommendations as well as 6 alternative screening strategies vs the 2013 USPSTF screening strategy. Strategies with a mean ICER lower than $100 000 per QALY were deemed cost-effective. RESULTS: The 2021 USPSTF recommendation was estimated to be cost-effective compared with the 2013 recommendation, with a mean ICER of $72 564 (range across 4 models, $59 493-$85 837) per QALY gained. The 2021 recommendation was not cost-effective compared with 6 alternative strategies that used the 20 pack-year criterion. Strategies associated with the most cost-effectiveness included those that expanded screening eligibility to include a greater number of former smokers who had not smoked for a longer duration (ie, ≤20 years and ≤25 years since smoking cessation vs ≤15 years since smoking cessation). In particular, the strategy that screened former smokers who quit within the past 25 years and began screening at age 55 years was associated with screening coverage closest to that of the 2021 USPSTF recommendation yet yielded greater cost-effectiveness, with a mean ICER of $66 533 (range across 4 models, $55 693-$80 539). CONCLUSIONS AND RELEVANCE: This economic evaluation found that the 2021 USPSTF recommendation for lung cancer screening was cost-effective; however, alternative screening strategies that maintained a minimum cumulative smoking exposure of 20 pack-years but included individuals who quit smoking within the past 25 years may be more cost-effective and warrant further evaluation.

Comparison of post-transplantation diabetes mellitus incidence and risk factors between kidney and liver transplantation patients.

BACKGROUND: Most prior studies characterizing post-transplantation diabetes mellitus (PTDM) have been limited to single-cohort, single-organ studies. This retrospective study determined PTDM across organs by comparing incidence and risk factors among 346 liver and 407 kidney transplant recipients from a single center. METHODS: Univariate and multivariate regression-based analyses were conducted to determine association of various risk factors and PTDM in the two cohorts, as well as differences in glucometrics and insulin use across time points. RESULTS: There was a higher incidence of PTDM among liver versus kidney transplant recipients (30% vs. 19%) at 1-year post-transplant. Liver transplant recipients demonstrated a 337% higher odds association to PTDM (OR 3.37, 95% CI (1.38-8.25), p<0.01). 1-month FBG was higher in kidney patients (135 mg/dL vs 104 mg/dL; p < .01), while 1-month insulin use was higher in liver patients (61% vs 27%, p < .01). Age, BMI, insulin use, and inpatient FBG were also significantly associated with differential PTDM risk. CONCLUSIONS: Kidney and liver transplant patients have different PTDM risk profiles, both in terms of absolute PTDM risk as well as time course of risk. Management of this population should better reflect risk heterogeneity to short-term need for insulin therapy and potentially long-term outcomes.

Incidence, Risk Factors, and Trends for Postheart Transplantation Diabetes Mellitus.

This retrospective study analyzed glycemic trends, incidence of post-transplant diabetes mellitus (PTDM) incidence and associated risk factors in a cohort of patients who underwent first-time heart transplantation (HT). Univariate analyses compared patient with and without pretransplant diabetes mellitus (DM). Multivariate regression analyses were conducted to determine association between PTDM and different risk factors. Finally, trends in glucometrics and other outcomes are described across follow-up time points. There were 152 patients who underwent HT between 2010 and 2015, 109 of whom had no pretransplant history of DM. PTDM incidence was 38% by the 1-year follow-up. Pretransplant body mass index (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.01 to 1.23, p = 0.03), insulin use during the final 24 hours of inpatient stay (OR 4.26, 95% CI 1.72 to 10.56, p <0.01), mean inpatient glucose (OR 2.21, 95% CI 1.33 to 3.69, p <0.01), and mean glucose in the final 24 hours before discharge (OR 1.29, 95% CI 1.03 to 1.60, p = 0.03) were associated with increased odds of PTDM at 1 year. In patients on insulin before discharge, blood glucose values were significantly higher compared with those who were not (136 mg/dl vs 114 mg/dl at 1 to 3 months, 112 vs 100 at 4 to 6 months, 109 vs 98 at 8 to 12 months, all p <0.01). This analysis improves understanding of PTDM incidence, glucometric trends, and risk differences by DM status in the HT population. Similar to liver and kidney patients, inpatient glucometrics may be informative of PTDM risk in HT patients. Guidelines for this population should be developed to account for risk heterogeneity and need for differential management.

Trends In State-Level Child Mortality, Maternal Mortality, And Fertility Rates In India.

Trends in child mortality, maternal mortality, and fertility in India reveal wide variation across states. As a whole, India performs worse than many other low- and middle-income countries, although its rates of improvement have recently increased. Differences in health systems and adopted policies may account for some of the variation across Indian states.

Health IT-assisted population-based preventive cancer screening: a cost analysis.

OBJECTIVES: Novel health information technology (IT)-based strategies harnessing patient registry data seek to improve care at a population level. We analyzed costs from a randomized trial of 2 health IT strategies to improve cancer screening compared with usual care from the perspective of a primary care network. STUDY DESIGN: Monte Carlo simulations were used to compare costs across management strategies. METHODS: We assessed the cost of the software, materials, and personnel for baseline usual care (BUC) compared with augmented usual care (AUC [ie, automated patient outreach]) and augmented usual care with physician input (AUCPI [ie, outreach mediated by physicians' knowledge of their patient panels]) over 1 year. RESULTS: AUC and AUCPI each reduced the time physicians spent on cancer screening by 6.5 minutes per half-day clinical session compared with BUC without changing cancer screening rates. Assuming the value of this time accrues to the network, total costs of cancer screening efforts over the study year were $3.83 million for AUC, $3.88 million for AUCPI, and $4.10 million for BUC. AUC was cost-saving relative to BUC in 87.1% of simulations. AUCPI was cost-saving relative to BUC in 82.5% of simulations. Ongoing per patient costs were lower for both AUC ($35.63) and AUCPI ($35.58) relative to BUC ($39.51). CONCLUSIONS: Over the course of the study year, the value of reduced physician time devoted to preventive cancer screening outweighed the costs of the interventions. Primary care networks considering similar interventions will need to capture adequate physician time savings to offset the costs of expanding IT infrastructure.

Comparing benefits from many possible computed tomography lung cancer screening programs: extrapolating from the National Lung Screening Trial using comparative modeling.

BACKGROUND: The National Lung Screening Trial (NLST) demonstrated that in current and former smokers aged 55 to 74 years, with at least 30 pack-years of cigarette smoking history and who had quit smoking no more than 15 years ago, 3 annual computed tomography (CT) screens reduced lung cancer-specific mortality by 20% relative to 3 annual chest X-ray screens. We compared the benefits achievable with 576 lung cancer screening programs that varied CT screen number and frequency, ages of screening, and eligibility based on smoking. METHODS AND FINDINGS: We used five independent microsimulation models with lung cancer natural history parameters previously calibrated to the NLST to simulate life histories of the US cohort born in 1950 under all 576 programs. 'Efficient' (within model) programs prevented the greatest number of lung cancer deaths, compared to no screening, for a given number of CT screens. Among 120 'consensus efficient' (identified as efficient across models) programs, the average starting age was 55 years, the stopping age was 80 or 85 years, the average minimum pack-years was 27, and the maximum years since quitting was 20. Among consensus efficient programs, 11% to 40% of the cohort was screened, and 153 to 846 lung cancer deaths were averted per 100,000 people. In all models, annual screening based on age and smoking eligibility in NLST was not efficient; continuing screening to age 80 or 85 years was more efficient. CONCLUSIONS: Consensus results from five models identified a set of efficient screening programs that include annual CT lung cancer screening using criteria like NLST eligibility but extended to older ages. Guidelines for screening should also consider harms of screening and individual patient characteristics.

Importance of Smoking Cessation in a Lung Cancer Screening Program.

Early detection of lung cancer and smoking cessation interventions can decrease lung cancer mortality, but information on the effectiveness and interaction between smoking cessation and lung cancer screening is sparse and inconsistent. This review aims to synthesize recent studies in two major areas of interest. First, we explore the interactions and potential for synergies between lung cancer screening programs and smoking cessation by summarizing reported changes in smoking behavior observed in major screening trials in the United States and Europe, as well as attempts to use smoking cessation interventions to augment the benefits from lung cancer screening programs. Second, we review the interaction between smoking habits and pre/post-operative pulmonary resection outcomes, including changes in smoking behavior post-diagnosis and post-treatment. Information from these areas should allow us to maximize benefits from smoking cessation interventions through the entire lung cancer screening process, from the screen itself through potential curative resection after diagnosis.

Specific killing of multiple myeloma cells by (-)-epigallocatechin-3-gallate extracted from green tea: biologic activity and therapeutic implications.

Epigallocatechin-3-gallate (EGCG), a polyphenol extracted from green tea, is an antioxidant with chemopreventive and chemotherapeutic actions. Based on its ability to modulate growth factor-mediated cell proliferation, we evaluated its efficacy in multiple myeloma (MM). EGCG induced both dose- and time-dependent growth arrest and subsequent apoptotic cell death in MM cell lines including IL-6-dependent cells and primary patient cells, without significant effect on the growth of peripheral blood mononuclear cells (PBMCs) and normal fibroblasts. Treatment with EGCG also led to significant apoptosis in human myeloma cells grown as tumors in SCID mice. EGCG interacts with the 67-kDa laminin receptor 1 (LR1), which is significantly elevated in myeloma cell lines and patient samples relative to normal PBMCs. RNAi-mediated inhibition of LR1 resulted in abrogation of EGCG-induced apoptosis in myeloma cells, indicating that LR1 plays an important role in mediating EGCG activity in MM while sparing PBMCs. Evaluation of changes in gene expression profile indicates that EGCG treatment activates distinct pathways of growth arrest and apoptosis in MM cells by inducing the expression of death-associated protein kinase 2, the initiators and mediators of death receptor-dependent apoptosis (Fas ligand, Fas, and caspase 4), p53-like proteins (p73, p63), positive regulators of apoptosis and NF-kappaB activation (CARD10, CARD14), and cyclin-dependent kinase inhibitors (p16 and p18). Expression of related genes at the protein level were also confirmed by Western blot analysis. These data demonstrate potent and specific antimyeloma activity of EGCG and provide the rationale for its clinical evaluation.

A clinically relevant SCID-hu in vivo model of human multiple myeloma.

We developed a novel in vivo multiple myeloma (MM) model by engrafting the interleukin 6 (IL-6)-dependent human MM cell line INA-6 into severe combined immunodeficiency (SCID) mice previously given implants of a human fetal bone chip (SCID-hu mice). INA-6 cells require either exogenous human IL-6 (huIL-6) or bone marrow stromal cells (BMSCs) to proliferate in vitro. In this model, we monitored the in vivo growth of INA-6 cells stably transduced with a green fluorescent protein (GFP) gene (INA-6GFP+ cells). INA-6 MM cells engrafted in SCID-hu mice but not in SCID mice that had not been given implants of human fetal bone. The level of soluble human IL-6 receptor (shuIL-6R) in murine serum and fluorescence imaging of host animals were sensitive indicators of tumor growth. Dexamethasone as well as experimental drugs, such as Atiprimod and B-B4-DM1, were used to confirm the utility of the model for evaluation of anti-MM agents. We report that this model is highly reproducible and allows for evaluation of investigational drugs targeting IL-6-dependent MM cells in the human bone marrow (huBM) milieu.

A SCID-hu in vivo model of human Waldenström macroglobulinemia.

The preclinical evaluation of investigational agents for Waldenström macroglobulinemia (WM) has been limited by the lack of in vivo models that enable the use of explanted patient cells. We describe here a novel in vivo model of human WM in severe combined immunodeficient (SCID) mice implanted with human fetal bone chips (SCID-hu mice) into which WM cells from patient bone marrow are engrafted directly into the human bone marrow (huBM) microenvironment. WM cells in SCID-hu mice produced human monoclonal paraprotein (immunoglobulin M [IgM] and/or kappa or lambda chain) detectable in mice sera. Immunohistochemical analysis of human bone retrieved from SCID-hu mice showed infiltration with CD20+, IgM+, and monotypic light chain+ lymphoplasmacytic cells. Mast cells were observed to be associated with the infiltrate in these sections. Treatment of SCID-hu mice bearing WM with rituximab induced tumor regression, associated with a decrease in serum paraprotein. This model, therefore, recapitulates the in vivo biology of WM and allows the study of novel investigational drugs targeting WM cells in the huBM milieu.