MTH1 (MutT Homolog1 )as MutT homologous en-zyme,is a nucleotide pyrophosphatase,mainly involved in DNA damage repair process,especially plays an important role in the process of DNA replication in tumor cells.Recent studies have found that MTH1’s function is responsible for the development of a variety of tumors.Studies have shown that,MTH1 can remove tumor cells’oxidative DNA elements detrimental to the function-al structure,protecting tumor cell division and proliferation, maintaining tumor cell survival,however,normal cells do not need MTH1.Therefore,MTH1 may be only closely associated with abnormal cell growth.This makes MTH1 as therapeutic tar-gets that have been paid much attention.This article reviewed the relationship of MTH1 and tumor,discussed the mechanisms of MTH1 in tumor growth MTH1 and tumor treatment,so as to provide reference for clinical research and treatment of tumor.

Aim To discuss the impact of important ac-tive ingredient of garlic diallyl sulfide———DATS on platelet activating factor (PAF ) mediated melanoma metastasis and its mechanisms.Methods ①MTT was used to test the effect of different concentrations of DATS on B16F10 and A375 melanoma cell growth number;②Scratch test and transwell were employed to test the effect of different concentrations of DATS on B16F10 and A375 melanoma cell migration;③ West-ern blot was used to test the effect of DATS on expres-sion of MMP-2,ERK,p38 induced by PFA;④Intrave-nous injection of tumor metastasis model was used to check the inhibition of DATS in PAF-mediated melano-ma metastasis.Results B16F10 cells relative growth rate fell to 73.21% and 48.78%,respectively,when DATS concentration reached 50 and 100 μmol·L-1 . DATS inhibited the levels of PAF-induced migration of melanoma cells B16F10 and vertical migration signifi-cantly,and inhibited B16F10 cells migration induced by PAF through inhibiting the expression of MMP-2, paxillin protein,FAK and other proteins.Conclusion DATS can significantly inhibit PAF-induced tumor metastasis, which is related to the inactivation of MAPKs.

Tumor necrosis factor receptor-associated protein 1 (TRAP1),as one of the main members of the heat shock protein 90 family, resists oxidative stress-induced apoptosis as well as predominantly maintains the integrity of mitochondria and cellu-lar homeostasis. Abnormal expression of TRAP1 was herein closely related to the onset and progression of a wide variety of tumors. As a key regulatory factor mediating energy metabolism within tumor cells, TRAP1 may be able to kill them by interfer-ing with such metabolism. More importantly, the abnormal ex-pression of TRAP1 played a less important role in normal cells, allowing TRAP1 to be a particularly attractive target as it can be used in tumor treatment or interference. The relationship be-tween abnormal expression of TRAP1 protein and tumor onset was reviewed. Besides, the mechanism by which disordered TRAP1 protein expression induced tumor formation was postula-ted, which may provide references for future research and clini-cal treatment.

Three forms of the major surface antigen (SAG1)of Toxoplasma gondii, that is the membrane form, the secrete form and the intracellular form, were constructed and used to immunize BALB/c mice. The humoral response in the mice immunized with the membrane form and the secrete form of SAG1 appeared earlier and stronger than those mice immunized with the intracellular form. Result from the challenging infection demonstrated that the protection in the mice immunized with the membrane and the secrete forms was also stronger than in the mice immunized with the intracellular form. We suggest that the immune efficiency of the three forms of SAG1 in the mouse model is different.

Tumor metastasis is one of the most important biologi-cal characteristics of malignant tumor, and it is also the main factor resulting in poor prognosis and leading to failure of treat-ment. In recent years, studies have shown that the extracellular matrix ( ECM) of tumor microenvironment plays a critical role in tumor metastasis. Tumor ECM fibrogenesis could form the cross-linked network structure, which not only provides nutrition and support to tumor, also it is necessary to tumor growth and inva-sion. These research results indicate that blocking ECM fibro-genesis may exert an inhibitory effect on tumor metastasis. Therefore, targeting ECM fibrogenesis has become a particularly attractive strategy as it can be used in the treatment of metasta-sis-related diseases. The ECM fibrogenesis in tumor is reviewed in this paper as well as the treatment strategies on tumor metas-tasis by targeting ECM fibrogenesis, which may provide refer-ences for follow-up research and clinical treatment.

Objective To evaluate the clinical outcome of kidney transplantation from donation after brain death(DBD)donors complicated with acute kidney injury(AKI).Methods Clinical data of 216 DBD donors were retrospectively analyzed,and they were divided into the AKI group(n=69)and control group(n=147)according to the Kidney Disease:Improving Global Outcomes(KDIGO)guidelines.Donors in the AKI group were further divided into the KDIGO stage 1 and stage 2-3 subgroups.One hundred and thirty-five recipients were assigned into the AKI group and 288 recipients in the control group.Postoperative recovery of renal function and clinical outcomes of the recipients were recorded.The risk factors of delayed graft function(DGF)were identified.Results The highest serum creatinine(Scr)level,Scr level before procurement,the highest blood sodium level and blood sodium level before procurement in the AKI group were higher than those in the control group.The application duration of vasopressors in the AKI group was longer than that in the control group.In the AKI group,the amount of fluid resuscitation within 48 h was higher,the HCO3-level at admission was lower,and the incidence of diabetes insipidus and hypotension was higher than those in the control group.The highest Scr level and the Scr level before procurement in KDIGO stage 2-3 donors were significantly higher than those in KDIGO stage 1 counterparts(all P＜0.05).Compared with the control group,the incidence of DGF and acute rejection was higher,the proportion of continuous renal replacement therapy was higher,the Scr level within postoperative 90 d was higher,and the urine amount within postoperative 3 d was less than those of recipients in the AKI group.Compared with KDIGO stage 1 recipients,KDIGO stage 2-3 recipients had higher Scr levels at postoperative 3,4,5 and 15 d,and less urine amount at postoperative 2 d(all P＜0.05).Univariate analysis showed that donor age,the highest Scr level,the highest blood sodium level and the amount of fluid resuscitation within 48 h were the risk factors for DGF in recipients after kidney transplantation.Multivariate analysis showed that donor age was the independent risk factor for DGF in recipients after kidney transplantation(all P＜0.05).Conclusions For the application of DBD donors complicated with AKI,active organ maintenance should be performed to alleviate AKI.It exerts no effect upon graft function and survival rate at postoperative 6 months,which may achieve equivalent efficacy as non-AKI donors and may be used as a source of extended criteria donor kidneys.

Objective:To analyze the sensitivity and specificity of SARS-CoV-2 nucleic acid testing in 20 348 close contacts of COVID-19 cases in different prevention and control stages in Guangzhou and to provide scientific evidence for optimizing epidemic response strategies.Methods:A total of 20 348 close contacts of COVID-19 cases in Guangzhou were traced between February 21 and September 22,2020. All the close contacts were tested for the nucleic acid of SARS-CoV-2. The sensitivity and specificity of nucleic acid testing and diagnosis in the different prevention and control stages were compared.Results:In 20 348 close contacts, 12 462 were males (61.24%), the median ( P 25, P 75) of age of them was 31.0 years (23.0,43.0), the median number ( P 25, P 75) of nucleic acid testing for them was 2.0 (1.0,3.0), and the median ( P 25, P 75) of their quarantine days was 12.0 (8.0,13.0) days, respectively. A total of 256 COVID-19 cases were confirmed in the close contacts after seven nucleic acid tests. In the 1 st, 2 nd, 3 rd and 7 th nucleic acid testing, the sensitivity and specificity were 69.14% and 99.99% (177 cases confirmed), 89.84% and 99.99% (230 cases confirmed), 97.27% and 99.99% (249 cases confirmed), and 100.00% and 99.98%, respectively. In the three stages of COVID-19 prevention and control in China: domestic case stage, imported case stage, and imported case associated local epidemic stage, the sensitivity of the 1 st nucleic acid testing was 70.68%, 68.00% and 67.35%, and the specificity was 99.98%, 100.00% and 100.00%, respectively. Conclusions:The sensitivity of nucleic acid testing in the close contacts at the different stages were consistent with slight decrease, which might be related to the increased proportion of asymptomatic infections in the late stage of epidemic prevention and control with COVID-19 in Guangzhou. It is suggested to give three nucleic acid tests to improve the sensitivity and reduce false negative risk.

Hepatic stellate cells (HSCs) represent a significant component of hepatocellular carcinoma (HCC) microenvironments which play a critical role in tumor progression and drug resistance. Tumor-on-a-chip technology has provided a powerful in vitro platform to investigate the crosstalk between activated HSCs and HCC cells by mimicking physiological architecture with precise spatiotemporal control. Here we developed a tri-cell culture microfluidic chip to evaluate the impact of HSCs on HCC progression. On-chip analysis revealed activated HSCs contributed to endothelial invasion, HCC drug resistance and natural killer (NK) cell exhaustion. Cytokine array and RNA sequencing analysis were combined to indicate the iron-binding protein LIPOCALIN-2 (LCN-2) as a key factor in remodeling tumor microenvironments in the HCC-on-a-chip. LCN-2 targeted therapy demonstrated robust anti-tumor effects both in vitro 3D biomimetic chip and in vivo mouse model, including angiogenesis inhibition, sorafenib sensitivity promotion and NK-cell cytotoxicity enhancement. Taken together, the microfluidic platform exhibited obvious advantages in mimicking functional characteristics of tumor microenvironments and developing targeted therapies.