High mobility group box 1 in the central nervous system: regeneration hidden beneath inflammation.

High-mobility group box 1 was first discovered in the calf thymus as a DNA-binding nuclear protein and has been widely studied in diverse fields, including neurology and neuroscience. High-mobility group box 1 in the extracellular space functions as a pro-inflammatory damage-associated molecular pattern, which has been proven to play an important role in a wide variety of central nervous system disorders such as ischemic stroke, Alzheimer's disease, frontotemporal dementia, Parkinson's disease, multiple sclerosis, epilepsy, and traumatic brain injury. Several drugs that inhibit high-mobility group box 1 as a damage-associated molecular pattern, such as glycyrrhizin, ethyl pyruvate, and neutralizing anti-high-mobility group box 1 antibodies, are commonly used to target high-mobility group box 1 activity in central nervous system disorders. Although it is commonly known for its detrimental inflammatory effect, high-mobility group box 1 has also been shown to have beneficial pro-regenerative roles in central nervous system disorders. In this narrative review, we provide a brief summary of the history of high-mobility group box 1 research and its characterization as a damage-associated molecular pattern, its downstream receptors, and intracellular signaling pathways, how high-mobility group box 1 exerts the repair-favoring roles in general and in the central nervous system, and clues on how to differentiate the pro-regenerative from the pro-inflammatory role. Research targeting high-mobility group box 1 in the central nervous system may benefit from differentiating between the two functions rather than overall suppression of high-mobility group box 1.

Protocol for the acquisition and maturation of oligodendrocytes from neonatal rodent brains.

The generation of an oligodendrocyte primary culture model encompassing the diverse stages of the lineage is essential for the in vitro research of oligodendrocyte physiology and pathophysiology. Here, we provide a protocol for generating oligodendrocytes from the neonatal rodent brain. We describe steps for isolating oligodendrocyte progenitor cells (OPCs) through differential centrifugation, their subsequent expansion, passaging, and differentiation. For complete details on the use and execution of this protocol, please refer to Kim et al.1.

Analysis of the spatial and morphological characteristics of oligodendrocytes from images of in vitro culture.

Oligodendrocytes (OLs) are glial cells responsible for the formation of myelin sheaths in the central nervous system. The characteristic features of the oligodendrocyte lineage, ranging from proliferative and migratory oligodendrocyte progenitor cells (OPC) to myelinating mature OLs, can be observed in vitro cultures of OL lineage cells. Here, we introduce a method for analyzing the spatial distribution of OPCs, which reflects their capacity for proliferation and migration, and the morphological complexity of mature OLs, which reflects their capacity for myelin formation, from immunostaining images of in vitro OL cultures. Through the methods described, we have demonstrated the tendency for OPCs to cluster in an environment with epidermal growth factor (EGF), and the differing morphological complexity of mature OLs according to culture medium and duration of differentiation.•The proliferative and migratory characteristics of OPCs can be evaluated by analyzing their spatial distribution.•The myelin-forming capacity of mature OLs can be measured by analyzing their morphological complexity.•Image-based analyses may be a substitute for more convoluted experiments to assess OL function.

Epidemiology of Respiratory Viruses in Korean Children Before and After the COVID-19 Pandemic: A Prospective Study From National Surveillance System.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic led to a decrease in the seasonal incidence of many respiratory viruses worldwide due to the impact of nonpharmaceutical interventions (NPIs). However, as NPI measures were relaxed, respiratory viral infections re-emerged. We aimed to characterize the epidemiology of respiratory viruses in Korean children during post-COVID-19 pandemic years compared to that before the pandemic. METHODS: A nationwide prospective ongoing surveillance study has been conducted for detection of respiratory viruses between January 2017 and June 2023. We included data on adenovirus (AdV), human bocavirus (HBoV), human coronavirus (HCoV), human metapneumovirus (HMPV), human rhinovirus (HRV), influenza virus (IFV), parainfluenza virus (PIV), and respiratory syncytial virus (RSV), which were detected in children and adolescents younger than 20 years. We analyzed the weekly detection frequency of individual viruses and the age distribution of the affected children. The study period was divided into prepandemic (2017-2019) and postpandemic (2021-2023) periods. RESULTS: A total of 19,589 and 14,068 samples were collected in the pre- and postpandemic periods, respectively. The overall detection rate of any virus throughout the study period was 63.1%, with the lowest occurring in the 2nd half of 2020 (50.6%) and the highest occurring in the 2nd half of 2021 (72.3%). Enveloped viruses (HCoV, HMPV, IFV, PIV, and RSV) almost disappeared, but nonenveloped viruses (AdV, HBoV, and HRV) were detected even during the peak of the COVID-19 pandemic. The codetection rate increased from 15.0% prepandemic to 19.1% postpandemic (P < 0.001). During the postpandemic period, a large out-of-season PIV and HMPV epidemic occurred, but the usual seasonality began to be restored in 2023. The mean age of children with each virus detected in 2023 was significantly greater than that in prepandemic years (P = 0.003 and 0.007 for AdV and HCoV, respectively; P < 0.001 for others). The mean age of children with IFV increased in 2022 (11.1 ± 5.2 years) from prepandemic years (7.9 ± 4.6 years) but decreased to 8.7 ± 4.1 years in 2023. CONCLUSION: With the relaxation of NPI measures, several seasonal respiratory viruses cocirculated with unusual seasonal epidemic patterns and were associated with increasing age of infected children.

A primary culture method for the easy, efficient, and effective acquisition of oligodendrocyte lineage cells from neonatal rodent brains.

Oligodendrocytes (OL) are myelin-forming glial cells in the central nervous system. In vitro primary OL culture models offer the benefit of a more readily controlled environment that facilitates the examination of diverse OL stages and their intricate dynamics. Although conventional methods for primary OL culture exist, their performance in terms of simplicity and efficiency can be improved. Here, we introduce a novel method for primary OL culture, namely the E3 (easy, efficient, and effective) method, which greatly improves the simplicity and efficiency of the primary OL culture procedure using neonatal rodent brains. We also provided the optimal media composition for the augmentation of oligodendrocyte progenitor cell (OPC) proliferation and more robust maturation into myelin-forming OLs. Overall, E3 offers an undemanding method for obtaining primary OLs with high yield and quality. Alongside its value as a practical tool, in vitro characteristics of the OL lineage additionally identified during the development of the E3 method have implications for advancing research on OL physiology and pathophysiology.

High Mobility Group Box 1 as an Autocrine Chemoattractant for Oligodendrocyte Lineage Cells in White Matter Stroke.

BACKGROUND: The migration of oligodendrocyte precursor cells (OPC) is a key process of remyelination, which is essential for the treatment of white matter stroke. This study aimed to investigate the role of HMGB1 (high mobility group box 1), a damage-associated molecular pattern released from dying oligodendrocytes, as an autocrine chemoattractant that promotes OPC migration. METHODS: The migratory capacity of primary cultured OPCs was measured using the Boyden chamber assay. The downstream pathway of HMGB1-mediated OPC migration was specified by siRNA-induced knockdown or pharmacological blockade of TLR2 (toll-like receptor 2), RAGE (receptor for advanced glycation end product), Src, ERK1/2 (extracellular signal-regulated kinase1/2), and FAK (focal adhesion kinase). Conditioned media were collected from oxygen-glucose deprivation-treated oligodendrocytes, and the impact on OPC migration was assessed. Lesion size and number of intralesional Olig2(+) cells were analyzed in an in vivo model of white matter stroke with N5-(1-iminoethyl)-L-ornithine (L-NIO). RESULTS: HMGB1 treatment promoted OPC migration. HMGB1 antagonism reversed such effects to untreated levels. Among the candidates for the downstream signal of HMGB1-mediated migration, the knockdown of TLR2 rather than that of RAGE attenuated the migration-promoting effect of HMGB1. Further specification of the HMGB1-TLR2 axis revealed that the phosphorylation of ERK1/2 and its downstream molecule FAK, rather than of Src, was decreased in TLR2-knockdown OPCs, and pharmacological inhibition of ERK1/2 and FAK led to decreased OPC migration. Oxygen-glucose deprivation-conditioned media promoted OPC migration, suggesting the autocrine chemoattractant function of HMGB1. In vivo, TLR2(-/-)-mice showed lesser intralesional Olig2(+) cells compared to wild-type controls in response to L-NIO induced ischemic injury regardless of HMGB1 administration. CONCLUSIONS: HMGB1, through the TLR2-ERK1/2-FAK axis, functions as an autocrine chemoattractant to promote OPC migration, which is an initial and indispensable step in remyelination. Thus, a novel treatment strategy for white matter stroke based on the HMGB1-TLR2 axis in the oligodendrocyte lineage could be feasible.

Isolation disrupts social interactions and destabilizes brain development in bumblebees.

Social isolation, particularly in early life, leads to deleterious physiological and behavioral outcomes. Here, we leverage new high-throughput tools to comprehensively investigate the impact of isolation in the bumblebee, Bombus impatiens, from behavioral, molecular, and neuroanatomical perspectives. We reared newly emerged bumblebees in complete isolation, in small groups, or in their natal colony, and then analyzed their behaviors while alone or paired with another bee. We find that when alone, individuals of each rearing condition show distinct behavioral signatures. When paired with a conspecific, bees reared in small groups or in the natal colony express similar behavioral profiles. Isolated bees, however, showed increased social interactions. To identify the neurobiological correlates of these differences, we quantified brain gene expression and measured the volumes of key brain regions for a subset of individuals from each rearing condition. Overall, we find that isolation increases social interactions and disrupts gene expression and brain development. Limited social experience in small groups is sufficient to preserve typical patterns of brain development and social behavior.

Forest management can mitigate negative impacts of climate and land-use change on plant biodiversity: Insights from the Republic of Korea.

Over the past century, the decline in biodiversity due to climate change and habitat loss has become unprecedentedly serious. Multiple drivers, including climate change, land-use/cover change, and qualitative change in habitat need to be considered in an integrated approach, which has rarely been taken, to create an effective conservation strategy. The purpose of this study is to quantitatively evaluate and map the combined impacts of those multiple drivers on biodiversity in the Republic of Korea (ROK). To this end, biodiversity persistence (BP) was simulated by employing generalized dissimilarity modeling with estimates of habitat conditions. Habitat Condition Index was newly developed based on national survey datasets to represent the changes in habitat quality according to the land cover changes and forest management, especially after the ROK's National Reforestation Programme. The changes in habitat conditions were simulated for a period ranging from the 1960s to the 2010s; additionally, future (2050s) spatial scenarios were constructed. By focusing on the changes in forest habitat quality along with climate and land use, this study quantitatively and spatially analyzed the changes in BP over time and presented the effects of reforestation and forest management. The results revealed that continuous forest management had a positive impact on BP by offsetting the negative effects of past urbanization. Improvements in forest habitat quality also can effectively reduce the negative impacts of climate change. This quantitative analysis of successful forest restoration in Korea proved that economic development and urbanization could be in parallel with biodiversity enhancement. Nevertheless, current forest management practices were found to be insufficient in fully offsetting the decline in future BP caused by climate change. This indicates that there is a need for additional measures along with mitigation of climate change to maintain the current biodiversity level.

A case of portal hypertension by presumed as plexiform neurofibroma at the hepatic hilum.

Neurofibromas can occur anywhere in the body, but they usually involve the head, neck, pelvis, and extremities. Abdominal visceral involvement is rare, and intrahepatic involvement is even less common. We describe a patient who suffered from plexiform neurofibromatosis with liver involvement. A 49-year-old man, who had previously been diagnosed with neurofibromatosis, underwent esophagogastroduodenoscopy and abdominal ultrasonography for screening purposes. Esophagogastroduodenoscopy showed grade 2 esophageal varices and abdominal ultrasonography showed conglomerated nodules with echogenic appearances in the perihepatic space. Magnetic resonance imaging showed presumed plexiform neurofibroma involving the lesser sac and hepatic hilum and encasing the common hepatic artery celiac trunk and superior mesenteric artery left portal triad. We report an unusual case of portal hypertension attributed to the compressive narrowing of the portal vein by presumed as plexiform neurofibroma at the lesser sac and hepatic hilum.

Increased frequency and severity of restless legs syndrome in patients with neuromyelitis optica spectrum disorder.

OBJECTIVES: To investigate the comorbidity of restless legs syndrome (RLS) and neuromyelitis optica spectrum disorder (NMOSD). METHODS: This study enrolled 159 NMOSD patients and 153 age- and gender-matched healthy controls. All participants completed a questionnaire based on the updated International Restless Legs Syndrome Study Group consensus criteria, the International RLS Severity scale, Epworth Sleepiness Scale, Fatigue Severity Scale, and Pittsburgh Sleep Quality Index, and were subsequently interviewed by a neurologist. The frequency and features of RLS were compared between NMOSD patients and healthy controls. The clinical and radiological characteristics of the NMOSD patients with and without RLS were also compared. RESULTS: The frequency and severity of RLS were significantly higher in NMOSD patients than in healthy controls (p = 0.015 for both) and NMOSD patients with RLS had a longer disease duration and more severe disability than those without RLS. CONCLUSIONS: This study indicated importance of considering RLS in NMOSD patients.

Leptomeningeal metastasis: Clinical experience of 519 cases.

BACKGROUND: Diagnosis of leptomeningeal metastasis (LM) has become increasingly common because of enhanced detection via routine use of magnetic resonance imaging (MRI) and longer survival of patients by better systemic control. We investigated clinical features and analyzed potential prognostic factors in a large cohort of patients with LM. METHODS: The clinical features of LM developing from systemic cancers were analyzed retrospectively in patients at the National Cancer Center during 2005-2014. RESULTS: A total of 519 patients were enrolled; 497 had solid, 19 had hematopoietic tumors and 3 had tumors of unknown etiology. Among the solid tumors, the most common primary tumor was lung cancer (334 patients), followed by breast cancer (96) and gastrointestinal cancer (39). Median age at onset was 56 years, and the median Karnofsky performance status (KPS) was 60. Thirty-five percent of patients were diagnosed by MRI alone, 22% by cerebrospinal fluid (CSF) cytology alone, and 42% by both. Treatment included chemotherapy alone in 45%, radiation therapy alone in 10%, and both in 17%; 28% received supportive care alone. Median overall survival was 3 months. KPS ≥70, CSF protein level ≤50 mg/dl at the diagnosis of LM, and active treatment were associated independently with longer overall survival. Upon subgroup analysis of lung cancer patients, non-small cell lung cancer was a favorable prognostic factor for overall survival. CONCLUSIONS: Despite improved diagnosis via MRI and vigorous therapy, most patients with LM had poor outcomes. However, patients with a high KPS or normal CSF protein levels had favorable prognoses upon active treatment.

Tumefactive demyelinating lesions as a first clinical event: Clinical, imaging, and follow-up observations.

BACKGROUND: Tumefactive demyelinating lesions (TDLs) are associated with a variety of demyelinating diseases in the central nervous system (CNS). However, there are no current guidelines describing how to classify and treat patients with this rare phenotype. Thus, the present study aimed to determine the long-term evolution and disease course of patients initially presenting with TDLs and to describe their clinical and radiographic characteristics. METHODS: From the National Cancer Center registry of inflammatory diseases of the CNS, 31 patients initially presenting with TDLs with follow-up for at least 12 months were enrolled and their demographic, clinical, and radiographic characteristics were evaluated. RESULTS: The median follow-up duration was 37.6 months, during which time 11 patients were diagnosed with neuromyelitis optica spectrum disorder (NMOSD), seven with multiple sclerosis (MS), and 11 remained idiopathic; six did not experience any further clinical events (isolated demyelinating syndrome), and five patients experienced recurrent demyelinating events that were not consistent with either MS or NMOSD. Of the remaining two patients, one was diagnosed with hyperthyroidism-associated demyelination and one with tacrolimus-induced demyelination. CONCLUSIONS: The majority of TDLs evolve into MS or NMOSD. However, despite extensive diagnostic work-ups and long-term follow-ups, the etiology of TDLs was unknown for some patients.

Liver dysfunction induced by systemic hypersensitivity reaction to lamotrigine: case report.

Lamotrigine is an anticonvulsant drug used to treat partial and generalized seizure disorders. Hypersensitivity to lamotrigine usually causes mild symptoms such as fever, rash, and slight invasion of internal organs. However, a 33-year-old male patient who was admitted with Stevens-Johnson syndrome after taking lamotrigine for 15 days experienced hepatic failure and died 5 days after admission. This case demonstrates the importance of realizing that lamotrigine can lead to fatal hepatic failure, and that tests for the normal liver function should be performed when administering lamotrigine.

Alkali-metal ion catalysis and inhibition in SNAr displacement: relative stabilization of ground state and transition state determines catalysis and inhibition in SNAr reactivity.

We report here the first observation of alkali-metal ion catalysis and inhibition in SNAr reactions. The plot of kobsd versus [alkali-metal ethoxide] exhibits downward curvature for the reactions of 1-(4-nitrophenoxy)-2,4-dinitrobenzene with EtOLi, EtONa, and EtOK, but upward curvature for the corresponding reaction with EtOK in the presence of 18-crown-6-ether (18C6). Dissection of kobsd into the second-order rate constants for the reactions with the dissociated EtO(-) and the ion-paired EtOM (i.e., k EtO - and kEtOM , respectively) has revealed that the reactivity increases in the order EtOLi

Measurement of antioxidant capacity using the biological antioxidant potential test and its role as a predictive marker of metabolic syndrome.

BACKGROUND/AIMS: Oxidative stress increases the risk of cardiovascular complications of metabolic syndrome (MetS). This study was conducted to examine the difference in antioxidant capacity according to the presence of MetS, and to characterize the association between antioxidant capacity and MetS-related factors. METHODS: We used the biological antioxidant potential (BAP) test to estimate antioxidant capacity. The BAP test has recently been used as an indicator of antioxidant capacity. We measured BAP levels in 45 patients with MetS (mean age, 44.6 ± 1.1 years) and 47 age- and sex-matched controls (mean age, 42.7 ± 1.1 years). To evaluate the association between antioxidant capacity and MetS, adiponectin, high-sensitivity C-reactive protein (hs-CRP), interleukin-6, tumor necrosis factor-α, and homeostatic model assessment for insulin resistance (HOMA-IR), linear regression and logistic analyses were performed. RESULTS: The mean BAP of the MetS group (1,937.3 ± 36.5 µmol/L) was significantly lower than that of the non-MetS group (2,101.7 ± 29.5 µmol/L). Also, the mean BAP was low in persons having low high density lipoprotein and high triglyceride. Reduced antioxidant capacity was significantly associated with adiponectin, HOMA-IR and hs-CRP after adjusting for age and sex. The odds ratios for MetS with BAP, log adiponectin, log HOMA-IR, and log hs-CRP were 0.63 (95% confidence interval [CI], 0.49 to 0.82), 0.22 (0.10 to 0.51), 14.24 (4.35 to 46.58), and 1.93 (1.36 to 2.75), respectively. CONCLUSIONS: Persons with MetS showed reduced antioxidant capacity. We identified relationships between antioxidant capacity measured by BAP test and MetS, as well as MetS-related factors, such as insulin resistance, hs-CRP, and adiponectin.

[A case of traumatic inferior mesenteric arteriovenous fistula].

Inferior mesenteric arteriovenous fistula is rare and may be congenital or acquired. Affected patients present with abdominal pain, mass, or manifestations of portal hypertension and bowel ischemia. Until now, inferior mesenteric arteriovenous fistula due to trauma has not been reported. Herein, we report a case of a 53-year-old woman who had inferior mesenteric arteriovenous fistula considered to have originated from remote blunt trauma that was successfully treated by surgical resection of only the arteriovenous fistula without colectomy. To our knowledge, this is the first case of traumatic inferior mesenteric arteriovenous fistula.

High serum C-reactive protein level predicts mortality in patients with stage 3 chronic kidney disease or higher and diabetic foot infections.

BACKGROUND: Diabetic patients are predisposed to foot infections because of vascular insufficiency and peripheral neuropathy. Diabetic foot infection is a common cause of mortality and lower extremity amputations (LEAs) in patients with chronic kidney disease (CKD). We evaluated the risk factors for mortality and LEAs in patients with stage 3 CKD or higher with diabetic foot infections. METHODS: We retrospectively evaluated a cohort of 105 CKD patients with diabetic foot infections between July 1998 and December 2011. We reviewed their demographic characteristics and laboratory parameters to evaluate the risk factors for mortality and amputations at 24 weeks after diagnosis of a diabetic foot infection. RESULTS: The mortality of the 105 enrolled CKD patients was 21% at 24 weeks after the diagnosis of a diabetic foot infection. Cox proportional regression analyses revealed that age 60 years or older [odds ratio (OR) 3.03, 95% confidence interval (CI) = 1.02-9.02, P = 0.047] and initial serum C-reactive protein (CRP) level ≥ 3 mg/dL (OR 3.97, 95% CI = 1.17-13.43, P = 0.027) were independent risk factors for mortality at 24 weeks. Twenty-four patients (23%) underwent LEAs. On Cox proportional regression analyses, peripheral vascular disease (OR=4.49, 95% CI=1.98-10.17, P=0.01) and cerebrovascular accident (OR 2.42, 95% CI=1.09-5.39, P=0.03) were independently associated with LEAs. CONCLUSION: This study showed that age and serum CRP level, were independent risk factors for mortality at 24 weeks in patients with stage 3-5 CKD with diabetic foot infections. Peripheral vascular disease and cerebrovascular accident were significantly associated with LEAs.

Interplay of reactive oxygen species, intracellular Ca2+ and mitochondrial homeostasis in the apoptosis of prostate cancer cells by deoxypodophyllotoxin.

The limited treatment option for recurrent prostate cancer and the eventual resistance to conventional chemotherapy drugs has fueled continued interest in finding new anti-neoplastic agents of natural product origin. We previously reported anti-proliferative activity of deoxypodophyllotoxin (DPT) on human prostate cancer cells. Using the PC-3 cell model of human prostate cancer, the present study reveals that DPT induced apoptosis via a caspase-3-dependent pathway that is activated due to dysregulated mitochondrial function. DPT-treated cells showed accumulation of the reactive oxygen species (ROS), intracellular Ca (i)(2+) surge, increased mitochondrial membrane potential (MMP, ΔΨ(m)), Bax protein translocation to mitochondria and cytochrome c release to the cytoplasm. This resulted in caspase-3 activation, which in turn induced apoptosis. The antioxidant N-acetylcysteine (NAC) reduced ROS accumulation, MMP and Ca (i)(2+) surge, on the other hand the Ca(2+) chelator BAPTA inhibited the Ca( i)(2+) overload and MMP without affecting the increase of ROS, indicating that the generation of ROS occurred prior to Ca(2+) flux. This suggested that both ROS and Ca( i)(2+) signaling play roles in the increased MMP via Ca (i)(2+)-dependent and/or -independent mechanisms, since ΔΨ(m) elevation was reversed by NAC and BAPTA. This study provides the first evidence for the involvement of both ROS- and Ca( i)(2+)-activated signals in the disruption of mitochondrial homeostasis and the precedence of ROS production over the failure of Ca(2+) flux homeostasis.

Cytotoxic effects of novel phytosphingosine derivatives, including N,N-dimethylphytosphingosine and N-monomethylphytosphingosine, in human leukemia cell line HL60.

Novel phytosphingosine derivatives have been developed based on the inhibition of sphingosine kinase, which has been implicated in cell growth and inhibition of ceramide-mediated apoptosis. This study evaluated the cytotoxic effects and underlying mechanisms of action of novel phytosphingosine derivatives, including N-monomethylphytosphingosine (MMPH) and N,N-dimethylphytosphingosine (DMPH) and the pegylated forms MMPH-PEG and DMPH-PEG, in human leukemia HL60 cells. In viability and proliferation assays using WST-1, all four drugs induced suppression of cell growth and viability in a concentration-dependent manner. Among them, DMPH had the highest antileukemic activity and induced apoptosis via caspase-8, caspase-3, and caspase-9 activation. The apoptotic effect was also associated with Fas/FasL upregulation, Bid cleavage, Bcl-2 downregulation, Bax upregulation, mitochondrial membrane depolarization, and cytochrome c release. DMPH decreased the phosphorylation of ERK and inhibited daunorubicin-induced ERK activation. Furthermore, DMPH displayed synergistic cytotoxicity with daunorubicin in a sequence-dependent manner. Our findings indicate that DMPH has potential as an effective cytotoxic agent for leukemia.

Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene polymorphisms as risk factors for hepatocellular carcinoma in a Korean population.

Hepatocellular carcinoma (HCC) is the third most frequent cause of cancer death in South Korea, but genetic susceptibility factors of HCC have not been examined extensively. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) play an essential role in both DNA synthesis and methylation and polymorphisms in the MTHFR gene, 677C>T, 1298A>C and the MTRR gene, 66A>G, are associated with several types of malignancy. In this study, the allelic frequencies and genotype distribution of three polymorphisms in the MTHFR and MTRR genes from 96 hepatocellular carcinoma (HCC) patients and 201 controls were examined to assess the association between these polymorphisms and the development of HCC in this Korean population. The 66AG+GG (G allele-bearing) genotype of the MTRR gene was significantly associated with an increased risk of HCC (odds ratio, OR, 1.687; 95% confidence interval, CI=1.022-2.787). Moreover, the combination of MTHFR 1298AA/MTRR 66AG+GG (OR=1.854, 95% CI=1.005-3.420) and MTHFR 1298AC+CC/MTRR 66AG+GG (OR=2.733, 95% CI=1.195-6.249) showed a significant association with HCC risk. In the data classified by age and etiology, MTRR 66A>G over the age of 65 years, MTHFR 1298A>C under the age of 65 years and the MTRR 66AG+GG genotype in the hepatitis B virus (HBV) patients were increased risk factors for the disease. The MTHFR 1298A>C and the MTRR 66A>G genotypes were associated with an increased risk of HCC in this Korean population. Further studies involving larger and varied populations could provide a potential tool for cancer risk assessment in patients who are at risk of developing HCC.