Vertical bony step between proximal and distal segments after mandibular setback is related with relapse: A cone-beam computed tomographic study.

INTRODUCTION: Vertical bony step (VBS) occurs between proximal and distal segments of the mandible during mandibular setback surgery with bilateral sagittal split ramus osteotomy. The purpose of this study was to investigate whether VBS is correlated with the relapse of mandibular setback using 3-dimensional models constructed from cone-beam computed tomography. METHODS: The subjects consisted of 30 patients who underwent bilateral sagittal split ramus osteotomy for a mandibular setback. Double jaw surgery was performed in 18 patients, and isolated mandibular setback surgery was performed in 12 patients. Cone-beam computed tomography scans were taken at pretreatment (T0), postsurgery (T1), and posttreatment (T2). Treatment changes and the correlations between measurements were evaluated. RESULTS: The mean mandibular setback was -11.9 mm, and the mean VBS was -5.6 mm. Correlations with the relapse of mandibular setback were found in the amount of mandibular setback (T1 - T0), development of VBS (T1 - T0), posterior movement of the proximal segment (T1 - T0), counterclockwise rotation of symphysis (T2 - T1), and the resolution of VBS (T2 - T1). CONCLUSIONS: The development and resolution of VBS were correlated with the relapse of mandibular setback. Minimizing VBS is recommended to reduce the relapse of mandibular setback.

Differential immune microenvironmental features of microsatellite-unstable colorectal cancers according to Fusobacterium nucleatum status.

It has been suggested that Fusobacterium nucleatum (Fn) may differentially impact tumor immune responses according to microsatellite instability (MSI) status in colorectal cancers (CRCs). We aimed to reveal the detailed relationship between intratumoral Fn and immune microenvironmental features in MSI-high CRCs. A total of 126 MSI-high CRCs were subjected to analyses for intratumoral Fn DNA load using quantitative PCR and for densities of tumor-infiltrating immune cells, including CD3+ T cells, CD4+ T cells, CD8+ T cells, FoxP3+ T cells, CD68+ macrophages, CD163+ macrophages, and CD177+ neutrophils, at invasive margin (IM) and center of tumor (CT) areas using computational image analysis of immunohistochemistry. Based on the Fn load, the 126 MSI-high CRCs were classified into Fn-high, -low, and -negative subgroups. The Fn-high subset of MSI-high CRCs was significantly correlated with larger tumor size and advanced invasion depth (p = 0.017 and p = 0.034, respectively). Compared with the Fn-low/negative subgroup, Fn-high tumors demonstrated significantly lower density of FoxP3+ cells in both IM and CT areas (p = 0.002 and p = 0.003, respectively). Additionally, Fn-high was significantly associated with elevated CD163+ cell to CD68+ cell ratio in only CT areas of MSI-high CRCs (p = 0.028). In conclusion, the Fn-enriched subset of MSI-high CRCs is characterized by increased tumor growth and invasion and distinct immune microenvironmental features, including decreased FoxP3+ T cells throughout the tumor and increased proportion of M2-polarized macrophages in the tumor center. These findings collectively support that Fn may be linked to pro-tumoral immune responses in MSI-high CRCs.

A surgery-first approach using single-jaw rotational mandibular setback in low-angle mandibular prognathism.

For the treatment of low-angle mandibular prognathism, rotational mandibular setback surgery is usually performed with Le Fort I maxillary osteotomy to rotate the maxillomandibular complex simultaneously. However, this maxillary surgery can be replaced with the orthodontic intrusion of maxillary posterior teeth. Single-jaw rotational mandibular setback surgery can be done with a surgery-first approach by planning orthodontic rotation of the maxillary occlusal plane with the simulation of the postsurgical forward mandibular rotation. This case report describes this approach applied to a 19-year-old female patient with low-angle mandibular prognathism but without maxillary deficiency. A Class II open bite was formed by the rotational setback surgery. During postsurgical orthodontic treatment, the maxillary total arch was distalized with maxillary molar intrusion using palatal mini-implants and lever. This case report demonstrates that orthodontic rotation of the maxillary occlusal plane and simulation of mandibular rotation can replace maxillary surgery and enable single-jaw rotational mandibular setback surgery with a surgery-first approach.

Maxillary molar intrusion and transverse decompensation to enable mandibular single-jaw surgery with rotational setback and transverse shift for a patient with mandibular prognathism and asymmetry.

When performing single-jaw surgery for mandibular setback, the distal segment of the mandible is brought distally along the occlusal plane, leaving the relationship of the B-point and pogonion unchanged. Double-jaw surgery for rotation of the maxillomandibular complex can be considered for solving this problem. However, maxillary surgery for rotational setback of the mandible can be replaced with orthodontic intrusion of the maxillary molars. Correcting the mandibular asymmetry that frequently accompanies mandibular prognathism often requires corrections of roll, yaw, and transverse shift of the mandible. Performing these corrections in mandibular single-jaw setback surgery requires transverse decompensation and orthodontic correction of maxillary occlusal-plane canting. This case report describes the simultaneous achievement of maxillary molar intrusion, transverse decompensation, and canting correction using a palatal lever supported by 2 midpalatal mini-implants. After creating a lateral open bite, mandibular setback surgery was performed with a 13.5° clockwise rotation, 2.9° roll correction, 3.5° yaw correction, and 3.5-mm transverse shift. The application of rotational setback significantly improved the facial esthetics. This case report demonstrates that orthodontic intrusion of the maxillary molars and transverse decompensation can replace maxillary surgery in the treatment of mandibular prognathism with asymmetry.

Combinatory low methylation statuses of SAT-α and L1 are associated with shortened survival time in patients with advanced gastric cancer.

BACKGROUND: L1 and SAT-α are repetitive DNA elements that undergo demethylation in association with cancerization. Unlike L1 hypomethaylation, nothing is known regarding the prognostic implication of SAT-α hypomethylation alongside L1 hypomethaylaton in gastric cancers. METHODS: Formalin-fixed paraffin-embedded samples from 492 cases of advanced gastric cancer were analyzed to determine their L1 and SAT-α methylation status using pyrosequencing methylation assay. RESULTS: L1 and SAT-α methylation statuses were correlated with clinicopathological parameters, including survival. L1 or SAT-α methylation levels were lower in gastric cancers with venous invasion or nodal metastasis than those without. L1 methylation was lower in gastric cancers with lymphatic emboli than in those with no lymphatic emboli, but was higher in gastric cancers with perineural invasion than in those with no perineural invasion. Multivariate survival analysis revealed that both tumoral L1 and SAT-α hypomethylations were found to correlate independently with OS (HR = 1.477; 95% CI 1.079-2.021 and HR = 1.394; 95% CI 1.011-1.922, respectively) and RFS (HR = 1.477; 95% CI 1.090-2.001 and HR = 1.516; 95% CI 1.106-2.078, respectively). Combined L1 and SAT-α hypomethylation turned out to correlate independently with OS (HR = 2.003; 95% CI 1.268-3.164) and RFS (HR = 2.226; 95% CI 1.411-3.510). CONCLUSION: Not only tumoral L1 hypomethylation, but also tumoral SAT-α hypomethylation was found to be independent prognostic parameters in patients with advanced gastric cancer. SAT-α methylation status can be used to further divide gastric cancers with L1 hypomethylation into subsets of gastric cancers with better and worse prognosis.

Tumoral LINE-1 hypomethylation is associated with poor survival of patients with intrahepatic cholangiocarcinoma.

BACKGROUND: DNA methylation changes occurring in cancer cells are featured with both promoter CpG island hypermethylation and diffuse genomic hypomethylation. Long interspersed element-1 (LINE-1) is repeated in an interspersed manner with an estimated 500,000 copies per genome. LINE-1 has its CpG sites of the 5' untranslated region methylated heavily in normal cells and undergoes demethylation in association with cancerization. However, little information is available regarding LINE-1 hypomethylation and its prognostic implication in intrahepatic cholangiocarcinomas. METHODS: A total of 172 cases of intrahepatic cholangiocarcinomas were analyzed for their methylation levels at four CpG sites of LINE-1 using bisulfite pyrosequencing. We examined the relation between tumoral LINE-1 methylation level and clinicopathological features, including survival. RESULTS: Tumor differentiation, lymphatic invasion, and T stage were associated with a low average methylation level of LINE-1 at the four CpG sites; LINE-1 methylation level tended to be lower in high-grade differentiation, lymphatic emboli, and higher T stage. LINE-1 hypomethylation was significantly linked with lower cancer-specific survival in patients with intrahepatic cholangiocarcinoma and was found to be an independent prognostic parameter. CONCLUSIONS: Our findings suggest that tumoral LINE-1 hypomethylation could be a molecular biomarker heralding poor prognosis of patients with intrahepatic cholangiocarcinoma. Our findings need to be validated in further study.

A study of correlations between cephalometric measurements in Koreans with normal occlusion by network analysis.

Analyzing the correlation between cephalometric measurements is important for improving our understanding of the anatomy in the oral and maxillofacial region. To minimize bias resulting from the design of the input data and to establish a reference for malocclusion research, the aims of this study were to construct the input set by integrating nine cephalometric analyses and to study the correlation structure of cephalometric variables in Korean adults with normal occlusion. To analyze the complex correlation structure among 65 cephalometric variables, which were based on nine classical cephalometric analyses, network analysis was applied to data obtained from 735 adults (368 males, 367 females) aged 18-25 years with normal occlusion. The structure was better revealed through weighted network analysis and minimum spanning tree. Network analysis revealed cephalometric variable clusters and the inter- and intra-correlation structure. Some metrics were divided based on their geometric interpretation rather than their clinical significance. It was confirmed that various classical cephalometric analyses primarily focus on investigating nine anatomical features. Investigating the correlation between cephalometric variables through network analysis can significantly enhance our understanding of the anatomical characteristics in the oral and maxillofacial region, which is a crucial step in studying malocclusion using artificial intelligence.

A Microphysiological Model to Mimic the Placental Remodeling during Early Stage of Pregnancy under Hypoxia-Induced Trophoblast Invasion.

Placental trophoblast invasion is critical for establishing the maternal-fetal interface, yet the mechanisms driving trophoblast-induced maternal arterial remodeling remain elusive. To address this gap, we developed a three-dimensional microfluidic placenta-on-chip model that mimics early pregnancy placentation in a hypoxic environment. By studying human umbilical vein endothelial cells (HUVECs) under oxygen-deprived conditions upon trophoblast invasion, we observed significant HUVEC artery remodeling, suggesting the critical role of hypoxia in placentation. In particular, we found that trophoblasts secrete matrix metalloproteinase (MMP) proteins under hypoxic conditions, which contribute to arterial remodeling by the degradation of extracellular matrix components. This MMP-mediated remodeling is critical for facilitating trophoblast invasion and proper establishment of the maternal-fetal interface. In addition, our platform allows real-time monitoring of HUVEC vessel contraction during trophoblast interaction, providing valuable insights into the dynamic interplay between trophoblasts and maternal vasculature. Collectively, our findings highlight the importance of MMP-mediated arterial remodeling in placental development and underscore the potential of our platform to study pregnancy-related complications and evaluate therapeutic interventions.

Radiologic study of the distance between the maxillary central incisor root and the incisive canal according to skeletal malocclusion classification.

The aim of this study was to evaluate the distance between the maxillary central incisor root and the incisive canal based on skeletal malocclusion classification and to analyze the morphology of the incisive canal using cone-beam computed tomography (CBCT). Skeletal malocclusion was categorized into Class I, II, and III using lateral cephalometric analysis. Measurements of the distance between the maxillary central incisor root and the incisive canal were taken at two levels: 2 mm (L1) and 4 mm (L2) superior to the labial cementoenamel junction of the maxillary central incisor. At L1, the distance was found to be closer in the Class II group compared to the Class I or Class III groups. Similarly, at L2, the Class II group exhibited a closer distance than the Class III group. Interestingly, females showed a closer distance compared to males at both L1 and L2. Further analysis revealed a significant gender difference in the Class I and III groups, but not in the Class II group. These findings emphasize the significance of evaluating the distance between the maxillary central incisor root and the incisive canal in patients with skeletal Class II malocclusion, regardless of gender.

Cross-shelf processes of terrigenous organic matter drive mercury speciation on the east siberian shelf in the Arctic Ocean.

The cross-shelf distributions of total mercury (THg), methylmercury (MeHg) and organic and inorganic matter, as well as the presence of the hgcA gene were investigated on the East Siberian Shelf (ESS) to understand the processes underlying the speciation of sedimentary Hg. Samples were collected from 12 stations grouped into four zones based on water depth: inner shelf (5 stations), mid-shelf (3 stations), outer shelf (2 stations), and slope (2 stations). The THg concentration in the surface sediment increased from the inner shelf (0.25 ± 0.023 nmol g-1) toward the slope (0.52 nmol g-1), and, when normalized to total organic carbon content, the THg showed a positive correlation with the clay-to-sand ratio (r2 = 0.48, p = 0.012) and degree of chemical weathering (r2 = 0.79, p = 0.0001). The highest MeHg concentrations (3.0 ± 1.8 pmol g-1), as well as peaks in the S/C ratio (0.012 ± 0.002) of sediment-leached organic matter, were found on the mid-shelf, suggesting that the activities of sulfate reducers control the net Hg(II) methylation rates in the sediment. This was supported by results from a principal component analysis (PCA) performed with Hg species concentrations and sediment-leached organic matter compositions. The site-specific variation in MeHg showed the highest similarity with that of CHONS compounds in the PCA, where Deltaproteobacteria were projected to be putative Hg(II) methylators in the gene analysis. In summary, the hydrodynamic sorting of lithogenic particles appears to govern the cross-shelf distribution of THg, and in situ methylation is considered a major source of MeHg in the ESS sediment.

Prognostic significance of extranodal extension of nodal metastasis in adenocarcinoma of the ampulla of Vater.

Although nodal metastasis (NM) is an important prognostic factor of ampullary adenocarcinoma, the prognostic implication of extranodal extension (ENE) is not well characterized. NM with ENE status was investigated in 279 surgically resected ampullary adenocarcinoma patients and compared with other clinicopathologic factors, including overall survival (OS) and recurrence-free survival (RFS). Expression of epithelial-mesenchymal transition (EMT) markers, including E-cadherin, Twist, and Snail, was assessed in a subset of the cohort. NM was observed in 94 cases (33.7%), of which ENE was observed in 32 cases (34%). NM with ENE was more frequently associated with tumors with poor differentiation than NM without ENE (P = .017). The 5-year OS and RFS rates of patients with NM and ENE was significantly worse (13.0% and 6.3%) than those with NM without ENE (37.7% and 21.4%) and those without NM (57.6% and 50.2%, respectively; P < .001). When pN category was matched, the OS and RFS was worse in patients with ENE than in those without ENE (P < .05). Moreover, the expression of E-cadherin and Twist was significantly different between NM areas with and without ENE (all, P < .001). Since ENE was associated with poorly differentiated ampullary adenocarcinomas and showed different expression of EMT markers, EMT could be a possible mechanism of ENE. Ampullary adenocarcinoma patients with ENE had worse OS and RFS than those without ENE. Therefore, evaluation of ENE can provide additional survival information for patients with surgically resected ampullary carcinoma.

Variation of the seed endophytic bacteria among plant populations and their plant growth-promoting activities in a wild mustard plant species, Capsella bursa-pastoris.

Recent studies have revealed that some bacteria can inhabit plant seeds, and they are likely founders of the bacterial community in the rhizosphere of or inside plants at the early developmental stage. Given that the seedling establishment is a critical fitness component of weedy plant species, the effects of seed endophytic bacteria (SEB) on the seedling performance are of particular interest in weed ecology. Here, we characterized the SEB in natural populations of Capsella bursa-pastoris, a model species of weed ecology. The composition of endophytic bacterial community was evaluated using deep sequencing of a 16S rDNA gene fragment. Additionally, we isolated bacterial strains from seeds and examined their plant growth-promoting traits. Actinobacteria, Firmicutes, Alpha-, and Gammaproteobacteria were major bacterial phyla inside seeds. C. bursa-pastoris natural populations exhibited variable seed microbiome such that the proportion of Actinobacteria and Alphaproteobacteria differed among populations, and 60 out of 82 OTUs occurred only in a single population. Thirteen cultivable bacterial species in six genera (Bacillus, Rhodococcus, Streptomyces, Staphylococcus, Paenibacillus, Pseudomonas) were isolated, and none of them except Staphylococcus haemolyticus were previously reported as seed endophytes. Eight isolates exhibited plant growth-promoting traits like phosphate solubilization activity, indole-3-acetic acid, or siderophore production. Despite the differences in the bacterial communities among plant populations, at least one isolated strain from each population stimulated shoot growth of either C. bursa-pastoris or its close relative A. thaliana when grown with plants in the same media. These results suggest that a weedy plant species, C. bursa-pastoris, contains bacterial endophytes inside their seeds, stimulating seedling growth and thereby potentially affecting seedling establishment.

Effects of Seed Endophytic Bacteria on Life History and Reproductive Traits in a Cosmopolitan Weed, Capsella bursa-pastoris.

Diverse bacteria inhabit plant seeds, and at least some of them can enhance plant performance at the early developmental stage. However, it is still inconclusive whether seed bacteria can influence post-germination traits and their contribution to plant fitness. To explore the evolutionary and ecological consequences of seed endophytic bacteria, we isolated four bacterial strains from the seeds of an annual weedy plant species, Capsella bursa-pastoris, and conducted a common garden experiment using seeds inoculated by isolated bacteria. Seeds infected by bacteria tended to germinate in spring rather than in autumn. Bacterial treatment also altered the expression of plant life history and reproductive traits, including flowering dates, rosette diameter at bolting, number of inflorescences, and fruit production. The results of the path analyses suggested that such effects of bacterial treatments were due to bacterial inoculation as well as germination delayed until spring. Spring germinants with bacterial infection showed a weaker association between post-germination traits and relative fitness than those without bacterial infection. These results suggest that seed bacteria likely affect the expression of post-germination traits directly or indirectly by delaying the germination season. An altered contribution of plant traits to relative fitness implies the influence of seed bacteria on the strength of natural selection.

Genotype-Specific Plastic Responses to Seed Bacteria under Drought Stress in Lactuca serriola.

Recent studies have demonstrated that seed-borne bacteria can enhance the performance of invasive plants in novel introduced habitats with environmental stresses. The effect of this plant-bacteria interaction may vary with plant species or even genotype; however, the genotype-dependent effects of seed bacteria have rarely been assessed. In this study, we examined the effects of bacterial strains isolated from seeds on the genotypes of an invasive xerophytic plant, Lactuca serriola. Plant genotypes were grown under drought conditions, and their plastic responses to bacterial infections were evaluated. Some genotypes produced more biomass, whereas others produced less biomass in response to infection with the same bacterial strain. Notably, the quantity of root-adhering soil depended on the bacterial treatment and plant genotypes and was positively correlated with the plastic responses of plant performance. Because tested bacteria could colonize the plant rhizosphere, bacterial infection appears to induce the differential formation of soil rhizosheaths among plant genotypes, consequently affecting the maintenance of soil water content under drought conditions. Given that drought tolerance is a critical attribute for the invasive success of L. serriola, these results imply that bacterial symbionts can facilitate the establishment of alien plant species, but their effects are likely genotype-specific.

Evaluation of Cortical Bone Formation on Mandibular Condyle in Asymptomatic Adolescents and Young Adults Using Cone-Beam Computed Tomography.

The aim of this study was to evaluate cortical bone formation on the mandibular condyle using cone-beam computed tomography (CBCT) in asymptomatic adolescents and young adults and to evaluate the relationship between age and sex. CBCT images that can evaluate the shape of the mandibular condyle were selected from asymptomatic patients aged 13−25. The degree of cortication on the mandibular condyle (CMC) was evaluated using CBCT images reconstructed in the axial, sagittal, and coronal planes. CBCT data of 829 patients (413 males, 416 females) were selected and then the left and right images of all patients were acquired; consequently, a total of 1658 temporomandibular joint-related images were evaluated in this study. The degree of CMC was correlated with age in men and women (p < 0.05). The frequency of CMC 0 disappeared in woman aged 20 years and in men aged 21 years. Cortical bone formation of the mandibular condyle was completed at age 22 years in women and 24 years in men. The degrees of cortical bone formation of the mandibular condyle between men and women showed significant differences between the ages of 15−19 and 22 years. This difference can be interpreted as a different mandible growth period between the sexes.

Invasive Lactuca serriola seeds contain endophytic bacteria that contribute to drought tolerance.

The mutualistic relationship between alien plant species and microorganisms is proposed to facilitate or hinder invasive success, depending on whether plants can form novel associations with microorganisms in the introduced habitats. However, this hypothesis has not considered seed endophytes that would move together with plant propagules. Little information is available on the seed endophytic bacteria of invasive species and their effects on plant performance. We isolated the seed endophytic bacteria of a xerophytic invasive plant, Lactuca serriola, and examined their plant growth-promoting traits. In addition, we assessed whether these seed endophytes contributed to plant drought tolerance. Forty-two bacterial species were isolated from seeds, and all of them exhibited at least one plant growth-promoting trait. Kosakonia cowanii occurred in all four tested plant populations and produced a high concentration of exopolysaccharides in media with a highly negative water potential. Notably, applying K. cowanii GG1 to Arabidopsis thaliana stimulated plant growth under drought conditions. It also reduced soil water loss under drought conditions, suggesting bacterial production of exopolysaccharides might contribute to the maintenance of soil water content. These results imply that invasive plants can disperse along with beneficial bacterial symbionts, which potentially improve plant fitness and help to establish alien plant species.

Whole-Slide Image Analysis Reveals Quantitative Landscape of Tumor-Immune Microenvironment in Colorectal Cancers.

PURPOSE: Despite the well-known prognostic value of the tumor-immune microenvironment (TIME) in colorectal cancers, objective and readily applicable methods for quantifying tumor-infiltrating lymphocytes (TIL) and the tumor-stroma ratio (TSR) are not yet available. EXPERIMENTAL DESIGN: We established an open-source software-based analytic pipeline for quantifying TILs and the TSR from whole-slide images obtained after CD3 and CD8 IHC staining. Using a random forest classifier, the method separately quantified intraepithelial TILs (iTIL) and stromal TILs (sTIL). We applied this method to discovery and validation cohorts of 578 and 283 stage III or high-risk stage II colorectal cancers patients, respectively, who were subjected to curative surgical resection and oxlaliplatin-based adjuvant chemotherapy. RESULTS: Automatic quantification of iTILs and sTILs showed a moderate concordance with that obtained after visual inspection by a pathologist. The K-means-based consensus clustering of 197 TIME parameters that showed robustness against interobserver variations caused colorectal cancers to be grouped into five distinctive subgroups, reminiscent of those for consensus molecular subtypes (CMS1-4 and mixed/intermediate group). In accordance with the original CMS report, the CMS4-like subgroup (cluster 4) was significantly associated with a worse 5-year relapse-free survival and proved to be an independent prognostic factor. The clinicopathologic and prognostic features of the TIME subgroups have been validated in an independent validation cohort. CONCLUSIONS: Machine-learning-based image analysis can be useful for extracting quantitative information about the TIME, using whole-slide histopathologic images. This information can classify colorectal cancers into clinicopathologically relevant subgroups without performing a molecular analysis of the tumors.

Treatment of Class I crowding using simple tubes bonded with customized resin coverings: A case report.

As an alternative to the conventional fixed appliance that uses orthodontic brackets, a simple round tube without a bonding base can be bonded to the tooth surface by covering the tube with flowable resin. In this technique, bent wires cannot be inserted into the simple tubes; therefore, repositioning of the simple tubes is often required for adjustments. To reduce repositioning of simple tubes, a dome-shaped resin covering of the simple tube can be designed with a customized in-and-out compensation, using three-dimensional computer-aided design software based on digital simulation of orthodontic tooth movement. In the present case, the use of simple tubes bonded with customized resin coverings in a Class I nonextraction case is described in a 17-year-old male, in whom moderate crowding of the anterior teeth was treated over an 8-month period. This case shows that simple tubes can be used as an alternative to brackets in some Class I nonextraction cases, with the potential benefit of reducing decalcification.

DLEC1 methylation is associated with a better clinical outcome in patients with intrahepatic cholangiocarcinoma of the small duct subtype.

Intrahepatic cholangiocarcinoma is a complex disease with three different histologic subtypes, the large duct, small duct, and bile ductular types. In the present study, we elucidated whether the three histological subtypes have differences in their methylation profiles and developed a DNA methylation marker that might help identify a subset of ICC with a different prognosis. We screened 113 promoter CpG island loci against 10 cases of intrahepatic cholangiocarcinoma and normal cystic ducts using the MethyLight assay and selected 30 CpG island loci with cancer-associated hypermethylation. Then, we analyzed 172 intrahepatic cholangiocarcinomas for the methylation state at these 30 loci. Six loci, including DLEC1, were more frequently methylated in the bile ductular type and small duct type, whereas six loci were more frequently methylated in the large duct type. Of these 30 loci, DLEC1 methylation was found mainly in the bile ductular type and small duct type but rarely in the large duct type. DLEC1 methylation was significantly associated with a better clinical outcome in intrahepatic cholangiocarcinomas of the small duct type but not of the bile ductular type. DLEC1 methylation was an independent prognostic variable in both cancer-specific survival and recurrence-free survival. For patients with intrahepatic cholangiocarcinoma of the small duct type (n = 68), DLEC1 methylation was found in 26 (38.2%) and was associated with a better clinical outcome for both cancer-specific survival and recurrence-free survival. Our findings suggest that DLEC1 methylation can be utilized to identify a subset with a better prognosis in intrahepatic cholangiocarcinomas of the small duct type.

CpG Island Methylation in Sessile Serrated Adenoma/Polyp of the Colorectum: Implications for Differential Diagnosis of Molecularly High-Risk Lesions among Non-dysplastic Sessile Serrated Adenomas/Polyps.

BACKGROUND: Although colorectal sessile serrated adenomas/polyps (SSA/Ps) with morphologic dysplasia are regarded as definite high-risk premalignant lesions, no reliable grading or risk-stratifying system exists for non-dysplastic SSA/Ps. The accumulation of CpG island methylation is a molecular hallmark of progression of SSA/Ps. Thus, we decided to classify non-dysplastic SSA/Ps into risk subgroups based on the extent of CpG island methylation. METHODS: The CpG island methylator phenotype (CIMP) status of 132 non-dysplastic SSA/Ps was determined using eight CIMP-specific promoter markers. SSA/Ps with CIMP-high and/or MLH1 promoter methylation were regarded as a high-risk subgroup. RESULTS: Based on the CIMP analysis results, methylation frequency of each CIMP marker suggested a sequential pattern of CpG island methylation during progression of SSA/P, indicating MLH1 as a late-methylated marker. Among the 132 non-dysplastic SSA/Ps, 34 (26%) were determined to be high-risk lesions (33 CIMP-high and 8 MLH1-methylated cases; seven cases overlapped). All 34 high-risk SSA/Ps were located exclusively in the proximal colon (100%, p = .001) and were significantly associated with older age (≥ 50 years, 100%; p = .003) and a larger histologically measured lesion size (> 5 mm, 100%; p = .004). In addition, the high-risk SSA/Ps were characterized by a relatively higher number of typical base-dilated serrated crypts. CONCLUSIONS: Both CIMP-high and MLH1 methylation are late-step molecular events during progression of SSA/Ps and rarely occur in SSA/Ps of young patients. Comprehensive consideration of age (≥ 50), location (proximal colon), and histologic size (> 5 mm) may be important for the prediction of high-risk lesions among non-dysplastic SSA/Ps.