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This paper is devoted to the study of the asset allocation problem for a DC pension plan with minimum guarantee constraint in a hidden Markov regime-switching economy. Suppose that four types of assets are available in the financial market: a risk-free asset, a zero-coupon bond, an inflation-indexed bond and a stock. The expected return rate of the stock depends on unobservable economic states, and the change of states is described by a hidden Markov chain. In addition, the CIR process is used to describe the evolution of the nominal interest rate. The contribution rate is also assumed to be stochastic. The goal of investment management is to minimize the convex risk measure of the terminal wealth in excess of the minimum guarantee constraint. First, we transform the partially observable optimization problem into the one with complete information using the Wonham filtering technique and deal with the minimum guarantee constraint by constructing auxiliary processes. Furthermore, we derive the optimal investment strategy by the BSDE approach. Finally, some numerical results are presented to illustrate the impacts of some important parameters on investment behaviors.

This paper studies a robust optimal investment–reinsurance problem for an insurer who possesses inside information on the financial market and the insurance business under model uncertainty. The insurer’s surplus process and the risky asset process in the financial market are assumed to be correlated jump diffusion processes with random coefficients. The inside information is modelled by a general random variable related to the future realizations of the surplus process and the risky asset process. Under the criterion of expected utility maximization, the optimal investment–reinsurance problem with inside information is transformed into an adapted stochastic control problem. By incorporating Knightian uncertainty into the model, we establish an adapted stochastic differential game problem with a nonstandard performance functional, which aims to select the robust optimal investment–reinsurance strategy for the insurer with inside information. The stochastic maximum principles are adopted to derive a characterization of the optimal strategy. Some interesting special cases are discussed and the corresponding optimal strategies are derived.

This paper studies an asset-liability management (ALM) problem under mean-variance criterion with inside information. The asset-liability manager is allowed to invest in a financial market composed...

This paper studies an optimal deterministic investment problem for a DC pension plan member with inflation risk. We describe the price processes of the inflation-indexed bond and the stock by a continuous diffusion process and a jump diffusion process with random parameters, respectively. The contribution rate linked to the income of the DC plan member is assumed to be a non-Markovian adapted process. Under the mean-variance criterion, we use Malliavin calculus to derive a characterization for the optimal deterministic investment strategy. In some special cases, we obtain the explicit expressions for the optimal deterministic strategies.

This paper studies a mean-variance asset–liability management (ALM) problem with uncertain time horizon and partial information. The ALM can invest in an incomplete financial market consisting of o...

Retraction of "MicroRNA-23 regulates the growth, metastasis and chemosensitivity of human gastric cancer cells by targeting MAP3K9", by Deping Li, Juan Wang, Yuanjian Hui, Yan Yang, Xingchun Peng, Shengbao Li, Chuantao Sun. JBUON 2020;25(5):2315-2321; PMID: 33277851 Following the publication of the above article, readers drew to our attention that part of the data was unreliable: Figures of this article appeared in other articles (by totally different authors). The authors were requested to provide the raw data and were also asked for an explanation to account for these concerns, but the Editorial Office did not receive any reply. Given above, we decided to retract this article. Authors were informed of the retraction. We thank the readers for bringing this matter to our attention. We apologize for any inconvenience it may cause.

Blockade of either Notch1 or PI3K/Akt pathway inhibits metastasis of gastric cancer. However, whether blockade of both pathways coordinately exerts such an effect remains unknown. In this study, we aimed to investigate the effects of combined treatment with Notch1 signaling blocker DAPT and PI3K/Akt signal blocker LY294002 on metastasis of gastric cancer. Notch intracellular domain (NICD) and phosphorylated Akt (p-Akt) levels in gastric cancer tissues and their adjacent normal tissue samples and gastric cancer SGC7901 and AGS cells and normal GES-1 cells were determined using immunohistochemistry and Western blotting. The effects of combined DAPT and LY294002 on metastasis of gastric cancer were evaluated by examining migration and invasion potential of SGC7901 cells using wound healing and transwell assays, determining changes in the levels of epithelial–mesenchymal transition biomarkers and MMP-9, Notch1, HES1, and phosphorylation of Akt in gastric cancer SGC7901 cells and/or AGS cells in vitro using Western blotting, and metastasis of gastric cancer to lungs in BALB/c nude mice after treatment. NICD and p-Akt levels were significantly higher in gastric cancer tissues and SGC7901 and AGS cells than those in the normal control and GES-1 cells. Migration and invasion potential of SGC7901 cells, EMT biomarkers and MMP-9 in SGC7901 cells, and metastasis of gastric cancer to lungs in mice were coordinately inhibited by DAPT and LY294002. In addition, DAPT and LY294002 coordinately inhibited the levels of Notch1, HES1, and p-Akt in gastric cancer cells. DAPT and LY294002 coordinately inhibited metastasis of gastric cancer through mutual enhancement.

This article is devoted to the study of a mean–variance problem for an insurer with deterministic reinsurance and investment strategy. The surplus process of the insurer and the financial risky ass...

The efficient therapeutic targets which could be utilized for gastric cancer are limited. In this context, this study was undertaken to evaluate possible anticancer activity of miR-23 against gastric cancer.The normal GES-1 and human AGS, SNU-1 and SNU-5 gastric cancer cells were used in this study. qRT-PCR was used for the determination of miR-23 expression. MTT assay was used for cell viability and acridine orange (AO)/ethidium bromide (EB) assay was used for detection of apoptosis. The experiments were performed in triplicate.The microRNA (miR)-23 was downregulated in gastric cancer cells and showed inhibitory effect on cell growth which was manifested as decline in cell survival. Additionally, the chemosensitivity of gastric cancer cells to cisplatin was enhanced with miR-23 overexpression. Furthermore, miR-23 also inhibited the migration and invasion of cancer cells. MAP3K9 was shown to be the target gene of miR-23 and silencing of MAP3K9 was seen to mimic the growth inhibitory effect of miR-23. Overexpression of MAP3K9 reversed the growth inhibition in miR-23 mimics transfected gastric cancer cells.miR-23 exerts growth inhibitory effect against gastric cancer cells and negatively regulates the cell migration and invasion along with enhancement of chemosensitivity of cancer cells.

This paper is devoted to the study of a risk-based optimal investment and proportional reinsurance problem. The surplus process of the insurer and the risky asset process in the financial m...

In this paper we consider the joint Laplace transform of occupation times over disjoint intervals for spectrally negative Levy processes with a general loss-carry-forward taxation structure. This tax structure was first introduced by Albrecher and Hipp in their paper in 2007. We obtain representations of the joint Laplace transforms in terms of scale functions and the Levy measure associated with the driven spectrally negative Levy processes. Two numerical examples, i.e. a Brownian motion with drift and a compound Poisson model, are provided at the end of this paper and explicit results are presented with discussions.

This paper considers an optimal investment and risk control problem under the criterion of logarithm utility maximization. The risky asset process and the insurance risk process are described by stochastic differential equations with jumps and anticipating coefficients. The insurer invests in the financial assets and controls the number of policies based on some partial information about the financial market and the insurance claims. The forward integral and Malliavin calculus for Levy processes are used to obtain a characterization of the optimal strategy. Some special cases are discussed and the closed-form expressions for the optimal strategies are derived.

// Xingchun Peng 2 , Jun Shi 3 , Wanqun Sun 1 , Xuzhi Ruan 2 , Yang Guo 2 , Lunhua Zhao 2 , Jue Wang 2 and Bin Li 1 1 Department of Pathology, Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, Fudan University, Shanghai Clincal Center, CAS, Shanghai, 200031, P. R. China 2 School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, Hubei, P. R. China 3 Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, P. R. China Correspondence to: Bin Li, email: libin15640@163.com Keywords: IL-6; cancer; meta-analysis; case-control studies Received: May 11, 2017 Accepted: November 17, 2017 Published: January 05, 2018 ABSTRACT IL-6 is critical for tumorigenesis. However, previous studies on the association of IL-6 promoter polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed this meta-analysis regarding the relationship between IL-6 promoter single nucleotide polymorphisms and cancer susceptibility and prognosis. Up to April 2017, 97 original publications were identified covering three IL-6 promoter SNPs. Our results showed statistically significant association between IL-6 promoter and cancer risk and prognosis. Subgroup analysis indicated that rs1800795 was significantly associated with increased risk of cervical cancer, colorectal cancer, breast cancer, prostate cancer, lung cancer, glioma, non-Hodgkin’s lymphoma and Hodgkin’s lymphoma but not gastric cancer and multiple myeloma. Furthermore, rs1800796 was significantly associated with increased risk of lung cancer, prostate cancer and colorectal cancer but not gastric cancer. Additionally, rs1800797 was significantly association with breast cancer, non-Hodgkin’s lymphoma, B-cell lymphoma and diffuse large B-cell lymphoma but not gastric cancer. Simultaneously, rs1800795 and rs1800796 were associated with a significantly higher risk of cancer in Asia and Caucasian, rs1800797 was associated with a significantly risk of cancer in Caucasian but not in Asia. Furthermore, IL-6 promoter polymorphisms were significantly associated with the prognosis of cancer. Considering these promising results, IL-6 promoter including rs1800795, rs1800796 and rs1800797 may be a tumor marker for cancer therapy.

// Jun Shi 1 , Weidong Leng 1 , Lunhua Zhao 2 , Cai Deng 1 , Chenli Xu 2 , Jue Wang 2 , Yu Wang 3 and Xingchun Peng 2, 3, 4 1 Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China 2 School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei, 442000, China 3 Department of Ultrasonography, Xiangyang No.1 People’s Hospital, Hubei University of Medicine, Xiangyang, Hubei, 441000, China 4 Department of Oncology, Suizhou Hospital, Hubei University of Medicine, Suizhou, Hubei, 441300, China Correspondence to: Xingchun Peng, email: 3537348127@qq.com Yu Wang, email: wangyu595@sina.com Keywords: cancer; tooth loss; dose–response relationship; meta analysis Received: April 27, 2017 Accepted: October 25, 2017 Epub: December 16, 2017 Published: March 13, 2018 ABSTRACT Conflicting results to identify the relationship between tooth loss and cancer risk. Therefore, a dose-response meta-analysis was performed to clarify and quantitative assessed the correlation between tooth loss and cancer risk. Up to March 2017, 25 observational epidemiological studies were included in current meta-analysis. Tooth loss was significantly associated with a higher risk of cancer. Additionally, tooth loss was associated with significantly a higher risk of esophageal cancer, gastric cancer, head and neck cancer, colorectal cancer, pancreas cancer, lung cancer, prostate cancer, bladder cancer and hematopoietic cancer. Subgroup analysis showed consistent findings. Furthermore, a significant dose-response relationship was observed between tooth loss and cancer risk. Increasing per 10 of tooth loss was associated with a 9% increment of cancer risk, 14% increment of esophageal cancer risk, 9% increment of gastric cancer risk, 31% increment of head and neck cancer risk, 4% increment of colorectal cancer risk, 7% increment of pancreas cancer risk, 19% increment of lung cancer risk, 2% increment of bladder cancer risk and 3% increment of hematopoietic cancer risk. Considering these promising results, tooth loss might be harmful for health. Large sample size, different ethnic population and different cancer type are warranted to validate this association.

// Jun Shi 1 , Weidong Leng 1 , Lunhua Zhao 2 , Chenli Xu 2 , Jue Wang 2 , Xiaoli Chen 2 , Yu Wang 3 and Xingchun Peng 2, 3, 4 1 Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China 2 School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei, 442000, China 3 Department of Ultrasonography, Xiangyang No.1 People’s Hospital, Hubei University of Medicine, Xiangyang, Hubei, 441000, China 4 Department of Oncology, Suizhou Hospital, Hubei University of Medicine, Suizhou, Hubei, 441300, China Correspondence to: Xingchun Peng, email: penxingchun@sina.com Yu Wang, email: wangyu595@sina.com Keywords: head and neck cancer, nonsteroidal anti-inflammatory drugs, chemoprevention, meta analysis Received: April 09, 2017 Accepted: September 18, 2017 Published: October 05, 2017 ABSTRACT Conflicting results identifying the relationship between nonsteroidal anti-inflammatory drugs using and head and neck cancer risk. Therefore, we performed this meta-analysis to clarify and quantitative assessed the relationship between nonsteroidal anti-inflammatory drugs using and head and neck cancer risk. Up to March 2017, 11 original publications were included in this meta-analysis. Our results showed statistically significant association between nonsteroidal anti-inflammatory drugs using and head and neck cancer risk reduction. Subgroups analysis indicated that Aspirin, COX 2 inhibitors, Ibuprofen and Other NSAIDs were associated with a significantly risk reduction of head and neck cancer. Furthermore, nonsteroidal anti-inflammatory drugs using was associated with a significantly lower risk of oral and oropharynx cancer, larynx cancer and hypopharynx cancer. In addition, increasing nonsteroidal anti-inflammatory drugs using (per 2 prescriptions/week increment) was associated with a 4% reduction in head and neck cancer risk, 5% reduction of aspirin using and 6% reduction of other nonsteroidal anti-inflammatory drugs using. Considering these promising results, increasing nonsteroidal anti-inflammatory drugs using might provide health benefits. More studies and large sample size are warranted to validate this association.

// Zhongqiang Yao 1 , Binhui Yang 1 , Zhongqiu Liu 1 , Wei Li 1 , Qihua He 1 , Xingchun Peng 2 1 Department of Medical Oncology, 3201 Affiliated Hospital of Medical College of Xi’an Jiaotong University, Hanzhong, 723000, Shanxi Province, P. R. China 2 Department of Centre of Oncology, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei Province, P. R. China Correspondence to: Xingchun Peng, email: 3537348127@qq.com Keywords: Bcl-2, cancer, meta-analysis, case-control studies Received: October 12, 2016 Accepted: January 29, 2017 Published: February 27, 2017 ABSTRACT Bcl-2 is critical for tumorigenesis. However, previous studies on the association of Bcl-2 promoter polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed this meta-analysis regarding the relationship between Bcl-2 promoter single nucleotide polymorphisms (SNPs) and cancer susceptibility and prognosis. Up to August 2016, 32 original publications were identified covering two Bcl-2 promoter SNPs (rs2279115 and rs1801018). Our results showed statistically significant association between rs2279115 and cancer susceptibility and prognosis in all four genetic models but not in rs1801018. Subgroups analysis indicated that rs2279115 was associated with a significantly higher risk of cancer susceptibility in Asia but not in Caucasian. Furthermore, rs2279115 was associated with a significantly higher risk in digestive system cancer and endocrine system cancer but not in breast cancer, respiratory cancer and hematopoietic cancer. Simultaneously, rs2279115 was correlated with a significantly higher risk of cancer prognosis in Asia but not in Caucasian. Considering these promising results, rs2279115 may be a tumor marker for cancertherapy in Asia. Sensitivity analysis show four gene model were stable, and no publication bias was observed in all four gene model. Large sample size, different ethnic population and different cancer type are warranted to validate this association.

This paper is devoted to the study of the optimal investment and risk control strategy for an insurer who has some inside information on the financial market and the insurance business. The insurer’s risk process and the risky asset process in the financial market are assumed to be very general jump diffusion processes. The two processes are supposed to be correlated. Under the criterion of logarithmic utility maximization of the terminal wealth, we solve our problem by using forward integral approach. Some interesting particular cases are studied in which the explicit expressions of the optimal strategy are derived by using enlargement of filtration techniques.

In this paper we consider the Markov-dependent risk model with tax payments in which the claim occurrence, the claim amount as well as the tax rate are controlled by an irreducible discrete-time Markov chain. Systems of integro-differential equations satisfied by the expected discounted tax payments and the non-ruin probability in terms of the ruin probabilities under the Markov-dependent risk model without tax are established. The analytical solutions of the systems of integro-differential equations are also obtained by the iteration method.

This paper is devoted to the study of optimization of investment, consumption and proportional reinsurance for an insurer with option type payoff at the terminal time under the criterion of exponential utility maximization. The surplus process of the insurer and the financial risky asset process are assumed to be diffusion processes driven by Brownian motions which are non-Markovian in general. Very general constraints are imposed on the investment and the proportional reinsurance processes. Based on the martingale optimization principle, we use BSDE and BMO martingale techniques to derive the optimal strategy and the optimal value function. Some interesting particular cases are studied in which the explicit expressions for the optimal strategy are given by using the Malliavin calculus.

This paper considers the optimal investment, consumption and proportional reinsurance strategies for an insurer under model uncertainty. The surplus process of the insurer before investment and consumption is assumed to be a general jump–diffusion process. The financial market consists of one risk-free asset and one risky asset whose price process is also a general jump–diffusion process. We transform the problem equivalently into a two-person zero-sum forward–backward stochastic differential game driven by two-dimensional Levy noises. The maximum principles for a general form of this game are established to solve our problem. Some special interesting cases are studied by using Malliavin calculus so as to give explicit expressions of the optimal strategies.

In this paper, we study the optimal proportional reinsurance and investment strategy for an insurer that only has partial information at its disposal, under the criterion of maximizing the expected utility of the terminal wealth. We assume that the surplus of the insurer is governed by a jump diffusion process, and that reinsurance is used by the insurer to reduce risk. In addition, the insurer can invest in financial markets. We give a characterization for the optimal strategy within a non-Markovian setting. Malliavin calculus for Levy processes is used for the analysis.

Melatonin is an important natural oncostatic agent, and our previous studies have found its inhibitory action on tumor angiogenesis, but the mechanism remains unclear. It is well known that vascular endothelial growth factor (VEGF) plays key roles in tumor angiogenesis and has become an important target for antitumor therapy. Pancreatic cancer is a representative of the most highly vascularized and angiogenic solid tumors, which responds poorly to chemotherapy and radiation. Thus, seeking new treatment strategies targeting which have anti-angiogenic capability is urgent in clinical practice. In this study, a co-culture system between human umbilical vein endothelial cells (HUVECs) and pancreatic carcinoma cells (PANC-1) was used to investigate the direct effect of melatonin on the tumor angiogenesis and its possible action on VEGF expression. We found HUVECs exhibited an increased cell proliferation and cell migration when co-cultured with PANC-1 cells, but the process was prevented when melatonin added to the incubation medium. Melatonin at concentrations of 1 μm and 1 mm inhibited the cell proliferation and migration of HUVECs and also decreased both the VEGF protein secreted to the cultured medium and the protein produced by the PANC-1 cells. In addition, the VEGF mRNA expression was also down-regulated by melatonin. Taken together, our present study shows that melatonin at pharmacological concentrations inhibited the elevated cell proliferation and cell migration of HUVECs stimulated by co-culturing them with PANC-1 cells; this was associated with a suppression of VEGF expression in PANC-1 cells.

Melatonin is an important natural oncostatic agent, and our previous studies have found its inhibitory action on tumor angiogenesis, but the mechanism remains unclear. It is well known that vascular endothelial growth factor (VEGF) plays key roles in tumor angiogenesis and has become an important target for antitumor therapy. Pancreatic cancer is a representative of the most highly vascularized and angiogenic solid tumors, which responds poorly to chemotherapy and radiation. Thus, seeking new treatment strategies targeting which have anti-angiogenic capability is urgent in clinical practice. In this study, a co-culture system between human umbilical vein endothelial cells (HUVECs) and pancreatic carcinoma cells (PANC-1) was used to investigate the direct effect of melatonin on the tumor angiogenesis and its possible action on VEGF expression. We found HUVECs exhibited an increased cell proliferation and cell migration when co-cultured with PANC-1 cells, but the process was prevented when melatonin added to the incubation medium. Melatonin at concentrations of 1 μm and 1 mm inhibited the cell proliferation and migration of HUVECs and also decreased both the VEGF protein secreted to the cultured medium and the protein produced by the PANC-1 cells. In addition, the VEGF mRNA expression was also down-regulated by melatonin. Taken together, our present study shows that melatonin at pharmacological concentrations inhibited the elevated cell proliferation and cell migration of HUVECs stimulated by co-culturing them with PANC-1 cells; this was associated with a suppression of VEGF expression in PANC-1 cells.