Regioselective 5-exo-dig (halo)cyclization of N-propargyloxycarbonyl guanidine derivatives under mild conditions.

A highly regioselective 5-exo-dig cyclization of aromatic N-propargyloxycarbonyl guanidines was developed via an Ag(I)-catalyzed intramolecular hydroamination reaction. This method features a fast reaction rate and mild reaction conditions. Furthermore, it was extended to access halogenated analogues via a one-pot Ag(I)-catalyzed bromocyclization reaction or an I2-mediated iodocyclization reaction with high E/Z selectivity.

7-Guanidinyl Coumarins: Synthesis, Photophysical Properties, and Application to Exploit the Pd-Catalyzed Release of Guanidines.

Molecular manipulation of guanidino-containing biomolecules in a cellular environment is fundamental to exploiting protein function and drug release, but currently, there is a lack of suitable methods for reaction screening and monitoring. To exploit the potential of the fluorescent method in this respect, herein, we evaluated a novel array of 7-guanidinyl coumarins by incorporating different substituted guanidino moieties into a coumarin scaffold. These compounds were prepared by guanidinylation reagent S-methylisothiourea or TFA-protected pyrazole-carboxamidine. Examination of their photophysical properties revealed that the fluorescence emission of alkyloxycarbonyl-substituted guanidinyl coumarin was significantly enhanced as compared with the unsubstituted analogue. This dramatic fluorescence difference enabled preliminary exploitation of the Pd-catalyzed release of allyloxycarbonyl (Alloc)-caged guanidinyl coumarin-6 in living cells.

ReACT (redox-activated chemical tagging) chemistry enables direct derivatization and fluorescence detection of S-adenosyl-L-homocysteine (SAH).

S-Adenosyl-L-homocysteine (SAH) is a universal byproduct and product inhibitor of the methyltransferase-catalyzed methylation reaction. Here based on ReACT (redox-activated chemical tagging) chemistry, direct derivatization and fluorescence measurement of SAH were achieved with features such as mild reaction conditions and simple operation.

Facile access to S-methyl dithiocarbamates with sulfonium or sulfoxonium iodide as a methylation reagent.

Efficient access to S-methyl dithiocarbamates was achieved with sulfonium or sulfoxonium iodide as a methylation reagent. This method is reliable for the synthesis of dithiocarbamates from primary or secondary amines, with sulfoxonium iodide demonstrating more robust methylation capability than sulfonium iodide. Moreover, it also enables facile access to S-trideuteromethyl dithiocarbamates via sulfoxonium metathesis between sulfoxonium iodide and DMSO-d6 with high yields.

The Progress of Colorectal Polyposis Syndrome in Chinese Population.

The pathogenesis, clinical phenotype, treatment strategy, and family management of hereditary tumor syndromes are different from those of sporadic tumors. Nearly a quarter of patients with colorectal cancer show significant familial aggregation and genetic predisposition, and 5 to 10% are associated with definite genetic factors. According to the clinical phenotype, it can be divided into nonpolyposis syndrome and polyposis syndrome. Among the polyposis syndrome patients with definite clinical symptoms, there are still some patients with unknown etiology (especially attenuated familial adenomatous polyposis), which is a difficult problem in clinical diagnosis and treatment. Therefore, for this rare disease, it is urgent to carry out multicenter studies, complete the gene variation spectrum, explore new pathogenic factors, and accumulate clinical experience. This article mainly introduces the research progress and related work of colorectal polyposis syndrome in China.

[Tea Polyphenols Regulate Renin-angiotensin-aldosterone System and Transforming Growth Factor-ß1/Smads Signaling Pathway in Heart Failure Rats].

Objective To investigate the effects of tea polyphenols on the renin-angiotensin-aldosterone system and the transforming growth factor-ß1(TGF-ß1)/Smads signaling pathway in heart failure rats.Methods SD rats were randomly assigned into a sham group,a model group,a captopril group(PC group),and a tea polyphenol group(TP group).The left anterior descending coronary artery was ligated with silk thread to establish the rat model of heart failure after myocardial infarction in the model group,PC group,and TP group,while it was not ligated in the sham group.Echocardiography was used to detect cardiac function.HE staining and Masson staining were conducted for the observation of myocardial pathological changes and myocardial fibrosis,respectively.Immunohistochemistry was employed to detect the expression of collagen Ⅰ and collagen Ⅲ.ELISA kits were used to measure the levels of angiotensin Ⅱ(AngⅡ),aldosterone(ALD),plasma renin activity(PRA),interleukin-1ß(IL-1ß),IL-6,and tumor necrosis factor-α(TNF-α).Western blotting was employed to determine the protein levels of TGF-ß1,phosphorylated Smad2(p-Smad2),Smad2,p-Smad3,and Smad3.Results Compared with the sham group,the model group showed disordered myocardial cells with obvious inflammatory cell infiltration,increased degree of myocardial fibrosis(t=9.748,P=0.001),elevated levels of collagen Ⅰ(t=11.754,P=0.001) and collagen Ⅲ(t=10.573,P=0.001),decreased ejection fraction(EF)(t=13.174,P=0.002) and left ventricular short axis shortening rate(LVFS)(t=11.853,P=0.001),and up-regulated expression of AngⅡ(t=4.246,P=0.001),ALD(t=5.385,P=0.004),PRA(t=4.386,P=0.004),IL-1ß(t=4.393,P=0.001),IL-6(t=6.375,P=0.002),and TNF-α(t=4.753,P=0.002),and up-regulated protein levels of TGF-ß1(t=6.365,P=0.001),p-Smad2/Smad2(t=13.755,P=0.001),and p-Smad3/Smad3(t=11.657,P=0.002).Compared with the model group,PC and TP alleviated the myocardial pathological changes,decreased the left ventricular end-diastolic diameter(LVEDd)(t=6.367,P=0.003 and t=5.264,P=0.003),left ventricular end-systolic diameter(LVEDs)(t=5.253,P=0.002 and t=5.974,P=0.001),heart mass index(HMI)(t=5.012,P=0.007 and t=4.953,P=0.005),left ventricular mass index(LVMI)(t=5.531,P=0.003 and t=5.483,P=0.004),and the degree of myocardial fibrosis(t=6.734,P=0.001 and t=5.362,P=0.001).Furthermore,they lowered the levels of collagen Ⅰ (t=5.373,P=0.001 and t=4.364,P=0.001) and collagen Ⅲ(t=6.764,P=0.001 and t=4.579,P=0.001),increased EF(t=11.264,P=0.002 and t=10.356,P=0.001) and LVFS(t=8.246,P=0.002 and t=7.824,P=0.001),and down-regulated the expression of AngⅡ(t=3.126,P=0.001 and t=2.853,P=0.001),ALD(t=3.854,P=0.004 and t=3.164,P=0.004),PRA(t=3.126,P=0.004 and t=3.063,P=0.004),IL-1ß(t=2.964,P=0.001 and t=2.765,P=0.001),IL-6(t=4.865,P=0.002 and t=4.275,P=0.002),and TNF-α(t=3.146,P=0.002 and t=2.973,P=0.002).In addition,they down-regulated the protein levels of TGF-ß1(t=4.657,P=0.001 and t=4.176,P=0.001),p-Smad2/Smad2(t=9.687,P=0.001 and t=6.753,P=0.001) and p-Smad3/Smad3(t=6.477,P=0.002 and t=4.754,P=0.002).Conclusion Tea polyphenols protect rats from heart failure by inhibiting the activation of renin-angiotensin-aldosterone system and TGF-ß1/Smads pathway.

Gemcitabine inhibits cisplatin resistance in cisplatin-resistant A549 cells by upregulating trx-interacting protein and inducing cell cycle arrest.

Cisplatin is a main chemotherapeutic drug used to treat non-small-cell lung cancer patients. However, these patients commonly face cisplatin resistance. The roles and underlying mechanisms of gemcitabine, irinotecan, pemetrexed and docetaxel used as single agents or combined with cisplatin for overcoming cisplatin-resistant non-small-cell lung cancer were explored in this study. MTT assays showed that gemcitabine alone exhibited stronger cytotoxicity on cisplatin-resistant A549 cells than irinotecan, pemetrexed and docetaxel. Meanwhile, gemcitabine combined with cisplatin showed a synergistic inhibitory effect on cisplatin-resistant cells. RNA sequencing and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analysis showed that cell cycle signaling pathways and trx-interacting protein were factors in the efficacy of the cotreatment. Flow cytometry and Western blot results showed that when cisplatin-resistant A549 cells were cotreated with gemcitabine and cisplatin, G0/G1 phase arrest occurred, and trx-interacting protein was upregulated. Silencing trx-interacting protein attenuated the response of the resistant cells to the drug combination. A trx-interacting protein agonist together with cisplatin showed an additive cytotoxic effect on the resistant cells compared with cisplatin alone. The gemcitabine and cisplatin combination, compared to gemcitabine or PBS alone, markedly suppressed the growth of cisplatin-resistant A549 tumors in vivo, accompanied by an increase in trx-interacting protein and a decrease in Ki67 expression. Therefore, we concluded that gemcitabine and cisplatin, as an FDA-approved combination, is a viable therapy for cisplatin-resistant non-small-cell lung cancer ex vivo and in vivo.

Simulation and experimental study of laser-induced thermal deformation of spectral beam combination grating.

The multilayer dielectric (MLD) grating is a critical device for combining multiple laser beams into a single beam in a spectral beam combining (SBC) system. We established a theoretical thermal deformation model of the laser-irradiated MLD grating. Thermal deformation on the surface of the grating is simulated according to a series of parameters including the laser irradiation time, laser power density, and substrate size. To verify the model, we exposed a 960 l/mm, 50×50×1.5 mm3 grating to a laser power density of 3.61 kW/cm2 and observed the temperature change. We used a Twyman-Green interferometer to measure the interference fringes on the grating surface. Based on the Fourier-transform method and a Zernike polynomial fitting method, the real-time grating surface profile is reconstructed. The results show that substrate thickness increase or area decrease can reduce thermal deformation, the average decreases are 18.3% and 19.9%, respectively. The discussion and analysis of the grating thermal deformation are potentially valuable for designing grating to decrease the thermal deformation and improve the combined beam quality of a SBC system.

Liquid-level sensing method based on differential pulse-width pair Brillouin optical time-domain analysis and a self-heated high attenuation fiber.

A liquid-level sensing method based on differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA) combining with a self-heated high attenuation fiber (HAF) is proposed, where the principle is to locate the temperature abruption position at the interface between liquid and air caused by their different thermal diffusion rates. A Panda polarization-maintaining fiber is used as the sensing optical fiber, which is tightly glued alongside a laser-powered HAF. Heated by a high-power laser, the temperature of the HAF can increase and exhibits approximately exponential attenuation with the light propagation direction, which induces a similar temperature distribution over the sensing fiber. By using a 5-cm spatial resolution DPP-BOTDA and a 1.4-W heating light, temperature distributions of the sensing fiber are measured for different water levels, and the results indicate that distributed liquid-level sensing with a range of 20 cm and a resolution of 1 cm is realized using our method.

Investigation of the correlation between charge and glycosylation of IgG1 variants by liquid chromatography-mass spectrometry.

A recombinant IgG1 monoclonal antibody (mAb) showed multiple charge variants in a cation exchange chromatography profile. To better understand the correlation between charge heterogeneity and glycosylation, a rapid reversed phase ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method with integrated mass analysis has been developed for simultaneous determination of N-terminal pyroglutamate, C-terminal lysine truncation, and Fc glycosylation. The results show that various degrees and/or types of N-terminal pyroglutamate formation and C-terminal lysine (Lys) cleavage account for the majority of charge heterogeneity; and the charge variants showed Fc glycosylation patterns in relation to their terminal modifications. The amount of G1F decreased in the basic variants, whereas Man5 and G0F-GN increased. The complement-dependent cytotoxicity (CDC) activity of purified charge variants also suggested the potential impact of the charge differences on the glycosylation profile.

Perioperative immunotherapy: the main clinical treatment for resectable non-small cell lung cancer.

Phase 3 clinical trials of perioperative immunotherapy for resectable non-small cell lung cancer (NSCLC): In recent years, immunotherapy for NSCLC is not only limited to advanced disease, but also has shown gratifying efficacy for early resectable NSCLC. With the publication of the results of several phase 3 clinical trials, perioperative immunotherapy will become one of the main treatment modalities for resectable NSCLC.

Anti-PD-(L)1-Based Neoadjuvant Therapy in Head and Neck Carcinoma: a Meta-analysis of Prospective Clinical Trials.

OBJECTIVE: This meta-analysis aims to evaluate the efficacy and safety of antiprogressive disease (PD)-(L)1-based neoadjuvant therapy in head and neck squamous cell carcinoma (HNSCC) patients and identify potential prognostic biomarkers. DATA SOURCES: Databases were systematically searched for prospective clinical trials evaluating the efficacy and safety of anti-PD-(L)1-based neoadjuvant therapy for HNSCC before January 12, 2024. REVIEW METHODS: We estimated the efficacy and safety of neoadjuvant immune checkpoint inhibitors. Subgroup and sensitivity analyses were further performed. RESULTS: A total of 570 patients from 20 studies were included. The pooled major pathological response (MPR), pathological complete response (pCR), and partial pathological response (PPR) rates were 30.7%, 15.3%, and 68.2%, respectively. Surgical complications, surgical delayed rate, all grade treatment-related adverse effects (TRAEs) and ≥Grade 3 TRAEs were 0.6%, 0.3%, 82.6%, and 9.7%, respectively. Best MPR or pCR rate was detected in patients receiving neoadjuvant anti-PD-(L)1 therapy + radiotherapy (with MPR rate of 75.5% and pCR rate of 51.1%) and neoadjuvant anti-PD-(L)1 therapy + chemotherapy groups (with MPR rate of 57.5% and pCR rate of 26.7%). No differences were detected in subgroups stratified by neoadjuvant treatment cycles, human papillomavirus (HPV) status, and tumor location. Patients with baseline Combined Positive Score (CPS) ≥ 20 have higher MPR and pCR rates compared to patients with CPS < 20. High Tumor Cell Proportion Score was also associated with MPR and pCR. Objective response rate is a strong predictor of MPR (odds ratio [OR] = 7.78, 95% confidence interval [CI] = 3.20%-18.91%) and pCR (OR = 3.24, 95% CI = 1.40%-7.48%). CONCLUSION: Anti-PD-(L)1-based neoadjuvant therapy was effective and safe for HNSCC patients.

Pharmacokinetic and bioequivalence study of two capecitabine tablets in Chinese patients with breast, colorectal or gastric cancer under fed condition: A multicentric, randomized, open-label, single-dose, two-period, two-way crossover clinical trial.

OBJECTIVE: The aim of this study was to examine the pharmacokinetics, bioequivalence, and safety of two tablet formulations of capecitabine 500 mg in Chinese patients with breast, colorectal or gastric cancer under fed condition. METHODS: A multicentric, randomized, open-label, single-dose, two-period, two-way crossover trial was conducted by randomizing a single oral dose of test (T) or reference (R, Xeloda®) capecitabine (500 mg) to patients of either sex with colon, colorectal or breast cancer under fed condition (high-fat and high-calorie diet). Pharmacokinetic parameters were calculated using non-compartmental methods. Patients were monitored for safety and tolerability throughout the study. RESULTS: 74 subjects were randomly enrolled. The T/R geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for Cmax, AUC0-t and AUC0-∞ of capecitabine were 96.60% (85.87-108.67%), 99.07% (95.40-102.89%), 99.17% (95.29-103.21%), respectively. All 90% CIs fell within the bioequivalence acceptance range of 80.00-125.00%. The common adverse events (AEs) included clinically significant laboratory abnormalities and gastrointestinal diseases. There were no serious adverse events (SAEs) or deaths during the study. No subject withdrew from the study due to AEs. CONCLUSION: Single oral intake of test and the reference capecitabine tablets were bioequivalent under fed condition and had similar favourable safety profiles in Chinese patients with breast, colorectal or gastric cancer. TRIAL REGISTRATION: chinadrugtrials.org.cn (CTR20182110).

Global burden of tracheal, bronchus, and lung cancer attributable to occupational carcinogens in 204 countries and territories, from 1990 to 2019: results from the global burden of disease study 2019.

BACKGROUND: Occupational-related cancers are a substantial global health issue. The largest proportion of occupational-related cancers is tracheal, bronchus, and lung (TBL) cancer. This study aimed to explore the geographical and temporal trends in occupational carcinogens related to TBL cancer. METHODS: Data on TBL cancer attributable to occupational carcinogens were collected from the Global Burden of Disease Study 2019. Numbers and age-standardized rates (ASRs) of deaths, disability-adjusted life years (DALYs), and corresponding average annual percentage change (AAPC) were evaluated and stratified by geographic location, socio-demographic index (SDI) quintiles, age, and sex. RESULTS: Globally, ASRs of deaths and DALYs in TBL cancer attributable to occupational carcinogens showed a downward trend (AAPC = - 0.69%, - 1.01%) while increases were observed in the low, low-middle, and middle SDI quintiles. Although males accounted for 82.4% and 81.5% of deaths and DALYs in 2019, respectively, it showed an upward trend of ASRs in females (AAPC = 0.33%, 0.02%). Occupational exposure to asbestos, silica and diesel engine exhaust were the top three causes of age-standardized TBL cancer deaths and DALYs. Over the past three decades, the percentage of age-standardized TBL cancer deaths and DALYs attributable to occupational asbestos and silica exposure decreased by 18.24, 6.71 and 20.52%, 4.00% globally, but increased significantly in lower SDI regions, while the burden attributable to occupational diesel engine exhaust exposure increased by 32.76, 37.23% worldwide. CONCLUSIONS: Occupational exposure remains an important risk factor for TBL cancer. The burden of TBL cancer attributable to occupational carcinogens showed obvious heterogeneity which decreased in higher SDI but increased in lower SDI regions. The burden of males was significantly higher than females, but the females showed an increasing trend. Occupational exposure to asbestos was the main causes of the burden. Therefore, effective prevention and control measures tailored to local conditions are necessary.

Postoperative recurrent patterns of gallbladder cancer: possible implications for adjuvant therapy.

BACKGROUND: Gallbladder cancer (GBC) is an uncommon malignancy with high recurrent rate and poor prognosis. This study investigates the recurrent patterns of postoperative GBC, with the aim to guide the adjuvant treatments, including the radiotherapy. METHODS: Retrospectively analyzed the 109 GBC patients who underwent surgery in our institution from January 2013 to 2018. Clinical follow-up revealed 54 recurrent cases, of which 40 had detailed locations of recurrence. The sites of recurrence were recorded and divided into the tumor bed, corresponding lymphatic drainage area, intrahepatic recurrence, and the other distant metastasis. RESULTS: The median follow-up time is 34 months (IQR: 11-64). The median disease-free survival (DFS) and overall survival (OS) were 48.8 months and 53.7 months, respectively. Through univariate analysis, risk factors for DFS and OS include tumor markers (CA199 and CEA), hepatic invasion, perineural invasion, lymphovascular invasion, TNM staging and tumor differentiation. Through multivariate analysis, risk factors for DFS include hepatic invasion and TNM staging, and for OS is TNM staging only. Of the 40 cases with specific recurrent sites, 29 patients (29/40, 72.5%) had recurrence in the potential target volume of postoperative radiotherapy (PORT), which include tumor bed and corresponding lymphatic drainage area. The common recurrent lymph node groups included abdominal para-aortic lymph node (No.16, 15/29), hepatoduodenal ligament lymph node (No.12, 8/29), retro-pancreatic head lymph node (No.13, 7/29) and celiac axis lymph node (No.9, 4/29). Twenty cases with recurrences inside the potential PORT target volume were accompanied by distant metastasis. Another 11 cases had distant metastasis alone, so totally 31 cases developed distant metastasis (31/40, 77.5%), including 18 cases with hepatic metastasis. CONCLUSION: The recurrence and metastasis rates are high in GBC and adjuvant therapy is needed. Up to 75% of the recurrent cases occurred in the potential target volume of postoperative radiotherapy, suggesting that postoperative radiotherapy has the possible value of improving local-regional control. The potential target volume of radiotherapy should include the tumor bed, No.8, No.9, No.11, No.12, No.13, No.14, No. 16a2, No. 16b1 lymph node groups.

Ferroptosis regulator FANCD2 is associated with immune infiltration and predicts worse prognosis in lung adenocarcinoma.

Lung adenocarcinoma (LUAD) remains one of the leading causes of cancer-related death. Although immunotherapy has been shown to improve survival in LUAD patients, only a select group of LUAD patients could benefit from it. The correlation between ferroptosis and the tumor immune environment requires further investigation in the setting of LUAD. An analysis using The Cancer Genome Atlas (TCGA)-LUAD cohort systematically evaluated the expression levels of ferroptosis regulators between LUAD and normal tissues and demonstrated the correlation of ferroptosis regulators with the immune checkpoint B7-H3 expression. Based on consensus clustering analysis, we divided LUAD patients into two subtypes according to the expression pattern of ferroptosis regulators. Cluster 2 patients showed more favorable overall survival (OS) (p < 0.001) and disease-free survival (DFS) (p < 0.001) than Cluster 1 patients. CIBERSORT analysis indicated that Cluster 1 patients harbored higher infiltrated levels of uncharacterized cells, CD4+ T cells (nonregulatory), and myeloid dendritic cells, while Cluster 2 patients were more correlated with B cells, M1 macrophages, natural killer cells (NK cells) and regulatory T cells (Tregs). More importantly, we identified FANCD2 as a potentially unfavorable prognostic factor that was overexpressed in LUAD and positively associated with the checkpoint molecule B7-H3 expression. In addition, higher FANCD2 expression was related to a higher tumor immune dysfunction and exclusion (TIDE) score, indicating lower responder rates to cancer immunotherapeutics. In summary, our study suggested a relationship between immune infiltration and ferroptosis and that FANCD2 is a potential biomarker for clinical outcomes and a therapeutic target for LUAD therapy concerning ferroptotic regulation. Our findings may help to advance personalized treatment and improve the prognosis of LUAD.

Oxidatively Damaged Nucleic Acid: Linking Diabetes and Cancer.

Significance: Our current knowledge of the mechanism between diabetes and cancer is limited. Oxidatively damaged nucleic acid is considered a critical factor to explore the connections between these two diseases. Recent Advances: The link between diabetes mellitus and cancer has attracted increasing attention in recent years. Emerging evidence supports that oxidatively damaged nucleic acid caused by an imbalance between reactive oxygen species generation and elimination is a bridge connecting diabetes and cancer. 8-Oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydroguanosine assume important roles as biomarkers in assessing the relationship between oxidatively damaged nucleic acid and cancer. Critical Issues: The consequences of diabetes are extensive and may lead to the occurrence of cancer by influencing a combination of factors. At present, there is no direct evidence that diabetes causes cancer by affecting a single factor. Furthermore, the difficulty in controlling variables and differences in detection methods lead to poor reliability and repeatability of results, and there are no clear cutoff values for biomarkers to indicate cancer risk. Future Directions: A better understanding of connections as well as mechanisms between diabetes and cancer is still needed. Both diabetes and cancer are currently intractable diseases. Further exploration of the specific mechanism of oxidatively damaged nucleic acid in the connection between diabetes and cancer is urgently needed. In the future, it is necessary to further take oxidatively damaged nucleic acid as an entry point to provide new ideas for the diagnosis and treatment of diabetes and cancer. Experimental drugs targeting the repair process of oxidatively generated damage require an extensive preclinical evaluation and could ultimately provide new treatment strategies for these diseases. Antioxid. Redox Signal. 37, 1153-1167.

Contribution of DNA methylation to the risk of hepatitis C virus-associated hepatocellular carcinoma: A meta-analysis.

DNA methylation is a crucial epigenetic modification in hepatocellular carcinoma (HCC), and hepatitis C virus (HCV) can induce hepatocarcinogenesis. Nevertheless, the interaction mechanism between DNA methylation and HCV infection in HCC is still ambiguous. In this study, we performed a comprehensive meta-analysis to assess the contribution of DNA methylation in HCV-associated HCC. After four steps of literature screening, we finally obtained 33 qualified case-control studies for this meta-analysis. These studies consisted of 587 HCV-positive cancer tissues and 326 HCV-negative cancer tissues. Our results revealed that four genes (p16, GSTP1, APC, and RUNX3) were more hypermethylated in the HCV-positive liver cancer tissues than in the HCV-negative liver cancer tissues. In addition, the p16 gene was more hypermethylated in the HCV-positive paracancerous tissues than in the HCV-negative paracancerous tissues. Subgroup meta-analysis by geographical populations showed that p16 methylation was significantly higher in HCV-positive cancerous tissues from Japanese and Chinese. Besides, p16 methylation was significantly higher among patients (> 60 years) but not among the others (≤ 60 years). However, there was no obvious association between DNA methylation and other clinicopathological characteristics, including gender, tumor size, differentiation, and clinical stage. Our study suggested that DNA methylation could become potential biomarkers for HCV-associated HCC. DNA methylation contributed to the risk of HCV-associated HCC.