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Background: Although the Korean Society for Cytopathology has developed educational goals as guidelines for cytopathology education in Korea, there is still no systematic approach to cytopathology education status for pathology residents. Furthermore, satisfaction with cytopathology education and with the outcome of the current training/educational program has not been investigated in Korea. This study aimed to obtain comprehensive data on the current state of cytopathology education for residents and evaluate education outcomes. Methods: An online survey was conducted in December 2020 for the board-certified pathologists and training residents registered as members of the Korean Society for Cytopathology. The questionnaire comprised questions that investigated the current status of cytopathology at each training institution, the degree of satisfaction with the work and education related to cytopathology, outcomes of cytopathology training, and educational accomplishments. Results: Of the participants surveyed, 12.3% (132/1,075) completed the questionnaire, and 36.8% (32/87) of cytopathology residents participated. The mean overall satisfaction with cytopathology education was 3.1 points (on a 1- to 5-point scale, 5: very satisfied). The most frequent suggestion among the free description format responses was to expand educational opportunities, such as online education opportunities, outside of the individual institutions. Conclusions: Our results showed that cytopathology training in Korea needs further improvement. We expect that this study will inform systematic training of competent medical personnel armed with broad cytopathology knowledge and strong problem-solving abilities.

Benign cartilaginous tumors, known as chondrogenic tumors, show cartilage components in the microscopic diagnosis. We present two clinical cases with cartilaginous tumors of the toes showing distinctive clinical manifestations. Two juvenile patients visited our outpatient clinic due to tumors with toenail deformities. A 10-year-old girl presented with a palpable mass with a nail deformity on the left third toe. The initial pathology report was soft tissue chondroma until complete resection. Another 15-year-old male patient visited the dermatology department with a toenail deformity and underwent a punch biopsy. The pathology report was fibrosis with myxoid degeneration. Excisional biopsies were performed for both patients. In the operative field, we observed exophytic tumors connected to the distal phalangeal bones. The final pathology reports were subungual osteochondroma on both patients. The specimen exhibited mature bone trabeculae with a focal cartilaginous cap. Benign cartilaginous tumors have a slow, progressive course and do not show significant symptoms. However, tumors in subungual areas are accompanied by toenail deformities and they can cause pain. Their clinical characteristics lead to a delayed diagnosis. Surgeons can be confused between soft tissue and chondrogenic tumors. When they conduct physical examinations, these categories should be considered in the differential diagnosis.

Purpose The programmed death ligand 1 (PD-L1) SP142 assay with a 1% immune cell (IC) cutoff is approved for the selection of advanced triple-negative breast cancer (TNBC) patients for atezolizumab treatment. We aimed to evaluate the interobserver concordance of PD-L1 scoring and inter-assay variability of various PD-L1 assays in TNBC. Methods Thirty patients with primary TNBC were selected, and SP142, SP263, 22C3, and E1L3N assays were performed. PD-L1 staining in ICs and tumor cells (TCs) was scored by 10 pathologists who were blinded to the assay. The interobserver concordance among pathologists and the inter-assay variability of the four PD-L1 assays were analyzed. For SP142, the intraobserver concordance among the six pathologists was analyzed after training. Results The adjusted means of PD-L1 IC scoring ranged from 6.2% to 12.9% for the four assays; the intraclass correlations showed moderate (0.584-0.649) reader concordance. The PD-L1 IC scoring with a 1% cutoff resulted in identical scoring in 40.0%-66.7% of cases and a poor to moderate agreement (Fleiss κ statistic [FKS] = 0.345-0.534) for the four assays. The SP142 assay had the widest range of positive rate (56.5%-100.0%), lowest number of cases with identical scoring, and lowest FKS at 1% cutoff. Pairwise comparison of adjusted means showed significantly decreased PD-L1 staining in SP142 compared with the other assays in both ICs and TCs. As for the intraobserver concordance in the SP142 assay, the overall percent agreement was 87.8% with a 1% IC cutoff. After training, the proportion of cases with identical scoring at a 1% IC cutoff increased to 70.0%; the FKS also increased to 0.610. Conclusion The concordance of PD-L1 IC scoring among pathologists was low, at the 1% cutoff for the SP142 assay without training. SP142 showed the lowest PD-L1 expression in both IC and TC.

This paper describes the calibration of a 10 nF capacitance standard traced to the DC quantum Hall resistance primary standard using a multi-purpose digital impedance bridge. The bridge can directly compare the unlike impedances in the fully digital (FD) mode, so the capacitance standard can be calibrated by a direct comparison against the AC resistance standard. The measurement ability of the bridge in the FD mode was evaluated in various angles, and the bridge voltage dependencies were improved by selecting appropriate impedances for the high current arms and also by using an additional injection circuit. Thereby, the measurement accuracy could reach up to 10−7 in relative terms. Based on the bridge evaluation, a 10 nF capacitance standard was calibrated against a 10 kΩ resistance standard, and the measurement value agreed with a reference value in the level of 10−7.

Background:The response of 1st-line EGFR-TKI treatment in advanced EGFR-mutated lung adenocarcinoma patients are highly effective, but its sustainability and clinical course are quite variable from patient to patient. In this study, we investigated the clinical impact of concomitant genetic mutations analyzed by targeted NGS on PFS and acquired resistance in advanced EGFR-mutated lung adenocarcinoma patients. Methods: Eighty-five advanced NSCLC patients harboring EGFR mutations were enrolled prospectively in multi-centers from 2019 to 2022 (NCT04122833). We performed the targeted next generation sequencing on 324 cancer-related genes by Foundation One CDx with pre-treated tumor samples. First- or second-generation EGFR-TKIs(gefitinib, afatinib, or erlotinib) were administered in 1st-line setting. After the progression, tissue re-biopsy or plasma liquid biopsy (FoundationOne Liquid CDx) for NGS if tissue biopsy is difficult or risk was performed. Results: Of the 85 patients (70.6% of female, 65.8% of nonsmoker, 56.4% of E19del and 38.8% of E21 L858R mutation), 50 patients experienced a disease progression in November, 2022. The median PFS was 20 months (95 %CI: 15.2-24.8). The most frequent co-mutations were TP53 (47.1%), CDKN2A/B loss (34.1%), MTAP loss (20%), NKX2-1amp(15.3%), MDM2amp (14.1%), RMB10, CCNE/CCND1 amp, NFKB1 amp (11.8%) and CDK4/6 amp (10.6%). Patients with TP53, CDK4/6 amp and MYC amp were independently associated with shorter PFS. In a multivariate analysis, tumors with copy number alterations such as CDK4/6 amp or Myc amp were also independently associated with shorter PFS. However, the CDKN2A/2B loss, MTAP loss, and MDM amp were not related with the PFS. In the number of co-mutations, patients harboring ≥5 co-mutations identified by NGS had shorter median PFS than patients with 0-1 or 2-4 co-mutations. (mPFS 0-1: 2-4: ≥5 co-mutations=35: 18: 9.3 months, p Conclusion: We have demonstrated that concomitant mutations detected by targeted NGS analysis provide significant impact on the drug response and clinical course of advanced EGFR-mutated adenocarcinoma patients treated by 1st-line EGFR-TKIs. It is suggested that targeted NGS along with PCR-based detection will be necessary for precision medicine-based individualized practice of 1st-line EGFR-TKI-based combination treatment. Citation Format: In Ae Kim, Seung Joon Kim, Sung Yong Lee, Chang Min Choi, Jae Cheol Lee, Tae Won Jang, Seung Hun Jang, Chan Kwon Park, Wan Seop Kim, Jae Young Hur, Hee Joung Kim, Young Whan Kim, Key Young Lee. Analysis of concomitant genetic alterations in advanced EGFR-mutated lung adenocarcinoma by targeted NGS: A multicenter prospective and real world study. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3886.

A measurement technique for a commercial four-terminal (4 T) air-dielectric capacitance standard set (Keysight 16380A) for frequencies from 1 kHz up to 13 MHz was developed for the accurate calibration of impedance analyzers. The technique consists of a measurement of capacitance at 1 kHz using a precision bridge, seven measurements of one-port driving point impedance (DPI) over 30 MHz using a vector network analyzer (VNA), and various numerical calculation procedures for parasitic component estimation and uncertainty propagation. The contribution from parasitic components in the frequency range of interest (FRI) from 1 to 13 MHz was estimated by extrapolation from the measured impedance using a VNA. A linear model for parasitic components was employed to extrapolate DPIs for a reliable estimation. The uncertainty of the calibration was estimated using Monte-Carlo (MC) simulation. The developed technique demonstrated better efficacy than others for the calibration of 100 pF and 1000 pF standards in FRI by applying simple, but reliable linear extrapolation models and Monte-Carlo (MC) simulation for uncertainty evaluation.

BACKGROUND: Extracellular vesicles (EVs) are membrane-bound and nanometer-sized particles released from most types of cells, containing double-stranded DNA reflecting mutational status of the parental tumor cells. Furthermore, epidermal growth factor receptor (EGFR) genotyping using EV-derived DNA (EV DNA) in bronchoalveolar lavage fluid (BALF) showed almost 100% sensitivity in patients with advanced non-small cell lung cancer (NSCLC). METHODS: We assessed the technical performance of DNA derived from BALF-EV (BALF EV DNA) in targeted next-generation sequencing (NGS) for detection and quantification of mutations compared with the matching tissue DNA in 20 lung adenocarcinomas. RESULTS: DNA yields, tumor purity, and depth of coverage were higher using the tissue DNA than using the BALF EV DNA. However, estimated library size was not significantly different between the two samples, and BALF EV DNA yielded longer fragments than tissue DNA. Overall mutation concordance between the two samples were 56% for nonsynonymous somatic mutations and increased to 81% for clinically significant mutations. By-variant sensitivity for clinically significant somatic mutations increased from 62% to 83% in the NGS of BALF EV DNA. Allele frequencies of EGFR and TP53 were higher in tissue DNA (10–25%) than in BALF EV DNA (

The prevalence of multiple lung cancers has been increasing recently. Molecular analysis of epidermal growth factor receptor (EGFR) mutations in individual tumors of multiple lung cancers is essential for devising an optimal therapeutic strategy. The EGFR mutation status in multiple lung cancers was evaluated to determine its therapeutic implications. In total, 208 tumors from 101 patients who underwent surgery for multiple lung cancers were analyzed. Individual tumors were subjected to histological evaluation and EGFR analysis using a real-time polymerase chain reaction. Additionally, EGFR-wildtype tumors were subjected to next-generation sequencing (NGS). EGFR mutations were detected in 113 tumors from 72 patients, predominantly in females (p < 0.001) and non-smokers (p < 0.001). Among patients with at least one EGFR-mutant tumor, approximately 72% of patients (52/72) had different EGFR mutations in individual tumors. NGS analysis of EGFR-wildtype tumors from 12 patients revealed four and eight cases with concordant and discordant molecular alterations, respectively. These findings revealed a high proportion of discordant EGFR mutations among multiple lung tumors. Hence, EGFR analysis of individual tumors of multiple lung tumors is essential for the evaluation of clonality and the development of an optimal treatment strategy.

To overcome the limitations of the tissue biopsy and plasma cfDNA liquid biopsy, we performed the EV-based BALF liquid biopsy of 224 newly diagnosed stage III-IV NSCLC patients and compared it with tissue genotyping and 110 plasma liquid biopsies. Isolation of EVs from BALF was performed by ultracentrifugation. EGFR genotyping was performed through peptide nucleic acid clamping-assisted fluorescence melting curve analysis. Compared with tissue-based genotyping, BALF liquid biopsy demonstrated a sensitivity, specificity, and concordance rates of 97.8%, 96.9%, and 97.7%, respectively. The performance of BALF liquid biopsy was almost identical to that of standard tissue-based genotyping. In contrast, plasma cfDNA-based liquid biopsy (n = 110) demonstrated sensitivity, specificity, and concordance rates of 48.5%, 86.3%, and 63.6%, respectively. The mean turn-around time of BALF liquid biopsy was significantly shorter (2.6 days) than that of tissue-based genotyping (13.9 days; p < 0.001). Therefore, the use of EV-based BALF shortens the time for confirmation of EGFR mutation status for starting EGFR-TKI treatment and can hence potentially improve clinical outcomes. As a result, we suggest that EV-based BALF EGFR testing in advanced lung NSCLC is a highly accurate rapid method and can be used as an alternative method for lung tissue biopsy.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis and a lack of targeted therapy. Overexpression ofFirst, using different web-based bioinformatics platforms (TIMER 2.0, UALCAN, and GEPIA 2), the expression ofThe expression of

Background Despite surgical resection, early lung adenocarcinoma has a recurrence rate of 20–50%. No clear predictive markers for recurrence of early lung adenocarcinoma are available. Targeted next-generation sequencing (NGS) is rarely used to identify recurrence-related genes. We aimed to identify genetic alterations that can predict recurrence, by comparing the molecular profiles of patient groups with and without recurrence. Methods Tissues from 230 patients with resected stage I–II lung adenocarcinoma (median follow-up: 49 months) were analyzed via targeted NGS for 207 cancer-related genes. The recurrence-free survival according to the number and type of mutation was estimated using the Kaplan–Meier method. Independent predictive biomarkers related to recurrence were identified using the Cox proportional hazards model. Results Recurrence was observed in 64 patients (27.8%). In multivariate analysis adjusted for age, sex, smoking history, stage, surgical mode, and visceral pleural invasion, the CTNNB1 mutation and fusion genes (ALK, ROS1, RET) were negative prognostic factors for recurrence in early-stage lung adenocarcinoma (HR 4.47, p = 0.001; HR 2.73, p = 0.009). EGFR mutation was a favorable factor (HR 0.51, p = 0.016), but the CTNNB1/EGFR co-mutations were negative predictors (HR 19.2, p p = 0.02). Conclusions: Targeted NGS can provide valuable information to predict recurrence and identify patients at high recurrence risk, facilitating selection of the treatment strategy among close monitoring and adjuvant-targeted therapy. Larger datasets are required to validate these findings.

Venous ulcers, ischemic wounds and skin lesions from autoimmune diseases are some examples of unhealing wounds. Practitioners treating such wounds should consider the possibility of skin metastasis of neoplasms, especially in patients with cancer. Treatment of cutaneous metastasis in cancer must include both surgical resection and chemotherapy. Here we present a patient who had lung cancer with skin metastasis. Though incidence of metastasis from lung cancer is known to be as low as 1% to 12%, its prognosis is poor. Also, the clinical features of these skin lesions tend to vary, often resulting in them being misdiagnosed as benign lesions. The diagnosis of malignancy for this particular case was delayed. After the metastatic lesion was diagnosed as such, surgical resection was performed and the defect caused by wide excision was covered by a superior gluteal artery perforator flap. Though the patient was administered an anticancer drug, the wound healed well after the operation.

Purpose Triple-negative breast cancer (TNBC) represents a major clinical challenge due to its aggressive and metastatic behavior and the lack of available targeted therapies. Therefore, therapeutic strategies are needed to improve TNBC patient management. Recently, atezolizumab and nab-paclitaxel chemotherapy has been approved by the Food and Drug Administration for the first-line treatment of patients with locally advanced and metastatic TNBC. The programmed death-ligand 1 (PD-L1) immunohistochemical SP142 assay was also approved as a companion diagnostic device for selecting TNBC patients for atezolizumab treatment. This study aimed to evaluate and compare the analytical performance of the PD-L1 22C3/SP263 assays in comparison with the SP142 assay for ≥ 1% immune cells (ICs). Methods Immunohistochemical expression for the PD-L1 22C3/SP263 assays, in comparison with the SP142 assay, was analyzed for the ≥ 1% ICs in 95 TNBCs. Results At the 1% cut-off value, the proportions of positive cases were 52.6% for the SP142 assay in infiltrating ICs and 50.5% and 52.6% for the 22C3 and SP263 assays in tumor cells, respectively. The PD-L1 SP263 assay had the highest while the PD-L1 22C3 assay had the lowest total positive expression rate at all cut-off values. The concordance rate between the assays was highest at a 1% cut-off value and decreased when the cut-off value increased. The concordance rate between the SP142 and SP263 assays at 1% cut-off was high, while in comparison, the concordance rate between the SP142 and 22C3 assays at 1% cut-off was relatively lower. Conclusion This study demonstrates that although the 22C3 assay at a 1% cut-off value compared with the PD-L1 SP142 assay at the clinically relevant cut-off shows comparable but not interchangeable analytical performance, the analytical performance of the SP263 assay at a 1% cut-off value shows interchangeable performance with the PD-L1 SP142 assay at the clinically relevant cut-off.

With advances in target therapy, molecular analysis of tumors is routinely required for treatment decisions in patients with advanced non-small cell lung cancer (NSCLC). Liquid biopsy refers to the sampling and analysis of circulating cell-free tumor DNA (ctDNA) in various body fluids, primarily blood. Because the technique is minimally invasive, liquid biopsies are the future in cancer management. Epidermal growth factor receptor (EGFR) ctDNA tests have been performed in routine clinical practice in advanced NSCLC patients to guide tyrosine kinase inhibitor treatment. In the near future, liquid biopsy will be a crucial prognostic, predictive, and diagnostic method in NSCLC. Here we present the current status and future perspectives of liquid biopsy in NSCLC.

Background/Aims We performed a large-scale, retrospective, nationwide, cohort study to investigate the risk factors for lung cancer among never-smoking Korean females. Methods The study data were collected from a general health examination and questionnaire survey of eligible populations conducted between January 1, 2003 and December 31, 2004; the data were acquired from the tailored big data distribution service of the National Health Insurance Service. After a 1-year clearance period, 5,860,922 of 6,318,878 never-smoking female participants with no previous history of lung cancer were investigated. After a median follow-up of 11.4 years, 43,473 (0.74%) participants were defined as “newly diagnosed lung cancer”. Results After adjusting for all variables at baseline, the variables older age, lower body mass index (BMI), less exercise, frequent alcohol drinking, meat-based diet, rural residence, and previous history of cancer were associated with a higher incidence of lung cancer. Low BMI (< 18.5 kg/m2: hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.27 to 1.40) was a significant independent risk factor; as BMI decreased, HR increased. Negative associations between BMI and lung-cancer development were also observed after controlling for age (p for trend < 0.001). Drinking alcohol one to two times a week (HR, 1.25; 95% CI, 1.21 to 1.28) and eating a meat-based diet (HR, 1.08; 95% CI, 1.01 to 1.15) were associated with lung-cancer incidence. Conclusions Modifiable baseline characteristics, such as BMI, exercise, alcohol consumption, and diet, are risk factors for lung-cancer development among never- smoking females. Thus, lifestyle modifications may help prevent lung cancer.

We developed an electron-counting technique for a self-referenced single-electron quantized current source of a single-electron-pump system and investigated the fidelity of our whole measurement process, including single-electron pumping and electron counting by a single-electron transistor (SET) with a charge-lock feedback loop. The device was fabricated monolithically using a two-dimensional electron system of a GaAs/AlGaAs hetero-junction. In addition to the probability of single-electron transfer, we also measured the current noise spectrum of the SET, from which its charge noise power [Formula: see text] was derived. The results show that the estimated charge noise of 2.2 [Formula: see text] for a semiconductor-based SET is comparable to that of metallic SETs.

Targeted NGS, widely applied to identify driver oncogenes in advanced lung adenocarcinoma, may also be applied to resected early stage cancers. We investigated resected EGFR-mutated lung adenocarcinoma mutation profiles to evaluate prognostic impacts. Tissues from 131 patients who had complete resection of stage I–IIIA EGFR-mutated lung adenocarcinoma were analyzed by targeted NGS for 207 cancer-related genes. Recurrence free survival (RFS) was estimated according to genetic alterations using the Kaplan–Meier method and Cox proportional regression analysis. The relapse rate was 25.2% (33/131). Five-year RFS of stages IA, IB, II, and IIIA were 82%, 75%, 35%, and 0%, respectively (p &lt, 0.001). RFS decreased with the number of co-mutations (p = 0.025). Among co-mutations, the CTNNB1 mutation was associated with short RFS in a multivariate analysis (hazard ratio: 5.4, 95% confidence interval: 2.1–14.4, p = 0.001). TP53 mutations were associated with short RFS in stage IB–IIIA (p = 0.01). RFS was shorter with EGFR exon 19 deletion (19-del) than with mutation 21-L858R in stage IB–IIIA tumors (p = 0.008). Among 19-del subtypes, pL747_P753delinS (6/56, 8.9%) had shorter RFS than pE746_A750del (39/56, 69.6%), the most frequent subtype (p = 0.004).

Background Extracellular vesicles (EV) have been proven to contain double-stranded DNA reflecting the mutational status of the parental tumor cells in non-small cell lung cancer (NSCLC), which can be translated into clinically useful EV-based liquid biopsy for Epidermal growth factor receptor (EGFR) genotyping using bronchoalveolar lavage fluid (BALF) obtained from tumor site. Methods Patients subjected for an initial lung cancer work-up underwent bronchoscopy and BALF was obtained from tumor site. After isolating EVs from BALF by ultracentrifugation, EV-derived DNA (EV DNA) was extracted for subsequent EGFR genotyping performed through peptide nucleic acid (PNA)-mediated Real-Time PCR. The sensitivity, specificity, and concordance rate of BALF EV-based EGFR genotyping were calculated in comparison to tissue genotyping. Results The average sensitivity and specificity of BALF EV-based EGFR genotyping were 76% and 87%, respectively, while the sensitivity significantly increased as the stage progressed. Especially, in stage IV, BALF EV-based EGFR typing identified all tissue-proven EGFR mutant cases (n=31) and detected 6 additional mutant cases. The concordance rate was 79% in stage I, 100% in stage II, 74% in stage III, and 92% in stage IV. As TNM stage advanced, especially in the presence of metastasis, concordance rate significantly increased (P

A national traceability chain from dc quantum Hall resistance (QHR) to capacitance has been established at Korea Research Institute of Standards and Science using various impedance standards and coaxial bridges. An ac–dc calculable resistance standard of nominal value of 12.9 $\text{k}\Omega $ was used as a transfer standard from dc to ac at the frequency of 1.541 kHz. Two ac coaxial bridges, developed by INRiM, were employed: a ratio bridge, linking the 103- $\text{k}\Omega $ ac resistor to the 12.9- $\text{k}\Omega $ ac–dc calculable resistor calibrated in terms of the dc QHR and a quadrature bridge, calibrating the 1000 pF capacitors versus the 103- $\text{k}\Omega $ ac resistors. The ratio bridge defines the 103- $\text{k}\Omega $ resistor as a two-terminal-pair (2TP) standard and the 12.9- $\text{k}\Omega $ resistor as a four-terminal-pair standard; a cable correction was applied to the 2TP defined standard. The stability of all standards has been monitored for more than 3 years to be within a few parts in 106. The capacitance value, obtained with the new traceability chain, shows an agreement (a few parts in 107) in a comparison with the reference values, traced from the National Institute for Standards and Technology (USA).

Porcine heart xenotransplantation is a potential treatment for patients with end-stage heart failure. To understand molecular mechanisms of graft rejection after heart transplantation, we transplanted a 31-day-old alpha-1,3-galactosyltransferase knockout (GTKO) porcine heart to a five-year-old cynomolgus monkey. Histological and transcriptome analyses were conducted on xenografted cardiac tissue at rejection (nine days after transplantation). The recipient monkey&rsquo, s blood parameters were analyzed on days &minus, 7, &minus, 3, 1, 4, and 7. Validation was conducted by quantitative real-time PCR (qPCR) with selected genes. A non-transplanted GTKO porcine heart from an age-matched litter was used as a control. The recipient monkey showed systemic inflammatory responses, and the rejected cardiac graft indicated myocardial infarction and cardiac fibrosis. The transplanted heart exhibited a total of 3748 differentially expressed genes compared to the non-transplanted heart transcriptome, with 2443 upregulated and 1305 downregulated genes. Key biological pathways involved at the terminal stage of graft rejection were cardiomyopathies, extracellular interactions, and ion channel activities. The results of qPCR evaluation were in agreement with the transcriptome data. Transcriptome analysis of porcine cardiac tissue at graft rejection reveals dysregulation of the key molecules and signaling pathways, which play relevant roles on structural and functional integrities of the heart.

The performance of our newly constructed cold-finger cryostat is investigated for quantum Hall resistance (QHR) and single-electron pump (SEP) devices. The cryostat features a vacuum-sealed sample chamber (SC) attached to a 0.3 K plate inside the inner vacuum can. The SC is designed to accommodate both the SEP and the QHR devices with a shielding partition between them. The measured QHR in the chamber approaches the nominal value for filling factor 2 within 20 parts in 109. The white-noise level of the SEP module, as obtained from the Allan deviation data, is 4.5 fA/ $\sqrt {\mathrm{ Hz}}$ . We also investigated the thermometry of the SC either under vacuum or filled with 3He gas. We calculated the thermal conductivity of the different heat conduction channels in the sample holder and found the dominant channel to be through the chip carriers not signal lines.

To make a graphene quantum Hall resistance (QHR) standard, there are many issues to overcome, such as the fabrication process and long-term stability. This paper shows the recent progress of graphene-based QHR at Korea Research Institute of Standards and Science on the graphene growth and the device fabrication. We synthesized high-quality epitaxial graphene (EG) grown on silicon carbide (SiC) substrate and introduced the high temperature annealing process between the fabrication process for making the Hall bar structure and the doping process for reducing the carrier concentration. By comparing the electrical property of graphene devices with the different quality, we show that these steps are crucial to make graphene-based QHR standard.

The performance of our newly constructed cold-finger cryostat is investigated for the precision measurement of quantum Hall resistance (QHR) and single-electron pump (SEP) current. The cryostat is featured by a vacuum sealed sample chamber that is attached to the 0.3 K-plate inside the inner vacuum can. The nominal base temperature of the sample chamber was 0.4 K. However, the electron temperature estimated with a single-electron transistor was approximately 0.6 K. Precision evaluation of a GaAs QHR device shows that the quantized Hall resistance is equivalent to the nominal value of $h/2e^{2}$ within one part in 108. The Allan deviation data for the SEP current is analyzed to be greater than those obtained from SEP in a wet 3He cryostat at Korean Research Institute of Standards and Science.

We developed a current-reversal operation method for single-parameter electron pumps, based on cryo-gate switches located between the ohmic contacts and quantum dot. The current reversal mode provided an enhanced signal-to-noise ratio, resulting in a reduction of the measurement time to reach the same relative measurement uncertainty, compared to a conventional unipolar current measurement method.

A digitally assisted coaxial bridge—mainly consisted of a ratio transformer and digital voltage sources—was set up in a 4-terminal-pair (4-TP) configuration for the precision capacitance measurements. The 10: 1 capacitance ratio was measured in the range of 1 pF $\sim 1\ \mu\mathrm{F}$ mainly at 1 kHz using the 4-TP bridge. The measurement results show a degree of equivalence from a few parts in 108 to 105 when compared with those obtained using 2-terminal-pair/3-terminal bridges. Moreover, the measurement frequency of the 4-TP bridge was varied from 50 Hz to 20 kHz. The Allan deviation measurements imply that the statistical uncertainty could be achieved a level of 10−9 at 1 kHz.

A single-electron pump based on a quantum dot is a promising candidate to realize the quantum current standard based on the new SI definition. In order to develop the quantum current standard, we fabricated two different types of single electron pumps based on GaAs/AlGaAs heterostructures by using KRISS nanofabrication facility. From the measurement results, we successfully observed the quantized current steps from the two differently designed pump devices.

We report on current-to-voltage conversion with an invariant $1\ \mathrm{M} \Omega$ quantized Hall array resistance. In a series connection of a battery-operated Zener voltage reference, a stable $1\ \mathrm{M} \Omega$ combination resistance reference, and the $1\ \mathrm{M} \Omega$ Hall array, the input current in the circuit and the current through the array are determined by a potentiometric method. The above two currents coincide with each other down to the relative measurement uncertainty of a part in 107 at $1\ \mu \mathrm{A}$ . This simple experiment shows that calibration-free precision current measurement, directly linked to the Planck constant $h$ and the elementary charge $e$ , can be performed by a Hall array combined with a Josephson effect-based quantum voltmeter.

This paper describes a calibration method for 10 nF capacitance standard from the primary standard of dc quantum Hall resistance using a multi-purpose digital coaxial bridge. The capacitance standard of 10 nF was calibrated by a direct comparison against the ac resistance standard of $10\ \mathrm{k}\Omega$ —its resistance value is traced to the quantum Hall resistance—using the digital bridge in the fully digital quadrature mode. The preliminary calibration value of the 10 nF was confirmed by comparing with a reference capacitance standard within uncertainty level of 10−6.

DNA replicase polymerase ε (POLE) is critical in proofreading and correcting errors of DNA replication. Low POLE expression plays a pivotal role in accumulation of mutations and onset of cancer, contributing to development and growth of tumor cells. The aim of this study is to reveal the survival, alternative genes and antitumoral immune activities in non-small cell lung cancer (NSCLC) patients with low POLE expression and provide treatment strategies that can increase their survival rates. This study investigated the clinicopathologic parameters, various tumor-infiltrating lymphocytes (TILs), endogenous retrovirus, molecular interactions and in vitro drug screen according to POLE mutation/expression in 168 and 1,019 NSCLC patients from the Konkuk University Medical Center (KUMC) and the Cancer Genome Atlas, respectively. We identified mutations of 75 genes in the sequencing panels, with POLE frame shift p.V1446fs being the most frequent (56.8%) in KUMC based on 170 targeted sequencing panels. Mutant and high expression of POLE correlated with favorable prognosis with increased TILs and tumor mutation burden, compared with wild type and low expression of POLE. We found specific molecular interactions associated with cell cycle and antigen presentation. An in vitro drug screen identified dasatinib that inhibited growth of the NSCLC cell line with low POLE expression. POLE could contribute to the future development of anticancer drugs for patients with NSCLC.