Nivolumab plus chemotherapy in the first-line setting has demonstrated clinical efficacy in patients with human epidermal growth factor receptor 2–negative advanced or metastatic gastric cancer, and is currently indicated as a standard treatment. Programmed death-ligand 1 (PD-L1) expression is an important biomarker for predicting response to anti–programmed death 1/PD-L1 agents in several solid tumors, including gastric cancer. In the CheckMate-649 trial, significant clinical improvements were observed in patients with PD-L1 combined positive score (CPS) ≥ 5, determined using the 28-8 pharmDx assay. Accordingly, an accurate interpretation of PD-L1 CPS, especially at a cutoff of 5, is important. The CPS method evaluates both immune and tumor cells and provides a comprehensive assessment of PD-L1 expression in the tumor microenvironment of gastric cancer. However, CPS evaluation has several limitations, one of which is poor interobserver concordance among pathologists. Despite these limitations, clinical indications relying on PD-L1 CPS are increasing. In response, Korean gastrointestinal pathologists held a consensus meeting for the interpretation of PD-L1 CPS in gastric cancer. Eleven pathologists reviewed 20 PD-L1 slides with a CPS cutoff close to 5, stained with the 28-8 pharmDx assay, and determined the consensus scores. The issues observed in discrepant cases were discussed. In this review, we present cases of gastric cancer with consensus PD-L1 CPS. In addition, we briefly touch upon current practices and clinical issues associated with assays used for the assessment of PD-L1 expression in gastric cancer.

Purpose: Immune checkpoint inhibitors (ICIs) have been shown significant oncological improvements in several cancers.However, ICIs are still in their infancy in hepatocellular carcinoma (HCC). Programmed cell death-ligand 1 (PD-L1), tumorinfiltrating lymphocytes (TILs), and epithelial-mesenchymal transition (EMT) have been known as prognostic factors in HCC. Therefore, we have focused on identifying the molecular mechanisms between each marker to evaluate a predictive role. Methods: Formalin-fixed paraffin-embedded samples were obtained from 166 patients with HCC who underwent surgery. The expression of PD-L1 and TILs and EMT marker were evaluated by immunohistochemical analysis. Results: The multivariate analysis showed that TIL expression (hazard ratio [HR], 0.483; 95% confidence interval [CI], 0.269–0.866; P = 0.015) were independent prognostic factors for overall survival. The prognostic factors for disease-free survival were EMT marker expression (HR, 1.565; 95% CI, 1.019–2.403; P = 0.005). Patients with high expression of TILs had significantly better survival compared to patients with low expression (P = 0.023). Patients who were TIL+/EMT– showed a significantly better prognosis than those who were TIL–/EMT+ (P = 0.049). Conclusion This study demonstrates that PD-L1 expression of TILs is closely associated with EMT marker expression in HCC. Clinical investigations using anti–PD-1/PD-L1 inhibitors in patients with EMT-associated PD-L1 upregulation are warranted.

Background: The purpose of this study was to evaluate the effect of vanishing twin (VT) on maternal serum marker concentrations and nuchal translucency (NT). Methods: This is a secondary analysis of a multicenter prospective cohort study in 12 institutions. Serum concentrations of pregnancy-associated plasma protein-A in the first trimester and alpha-fetoprotein (AFP), total human chorionic gonadotrophin, unconjugated estriol, and inhibin A in the second trimester were measured, and NT was measured between 10 and 14 weeks of gestation. Results: Among 6,793 pregnant women, 5,381 women were measured for serum markers in the first or second trimester, including 65 cases in the VT group and 5,316 cases in the normal singleton group. The cases in the VT group had a higher median multiple of the median value of AFP and inhibin A than the normal singleton group. The values of other serum markers and NT were not different between the two groups. After the permutation test with adjustment,AFP and inhibin A remained significant differences. The frequency of abnormally increased AFP was also higher in the VT group than in the normal singleton group. Conclusion VT can be considered as an adjustment factor for risk assessment in the secondtrimester serum screening test.

Purpose: Macular edema including cystoid macular edema is one of the main causes of unfavorable visual outcomes after cataract surgery. The macular thickness and the occurrence of macular edema after uncomplicated cataract surgery was evaluated using optical coherence tomography (OCT) in this study. Methods: Macular map images were taken by OCT before surgery and at 1 week, 1 month, and 2 months postsurgery. The subjects were classified into two groups (group 1, patients with no macular edema; group 2, patients with macular edema). Group 2 was defined as increase in central macular thickness (CMT) by 30% compared with that before surgery. The risk factors for macular edema were evaluated. Group 2 was divided into two subgroups: subclinical macular edema (group 2A) and cystoid macular edema (group 2B) and they were assessed in terms of the clinical course of best-corrected visual acuity and CMT. Results: A total of 376 patients were enrolled in this study, of which 36 (9.57%, group 2) showed macular edema measured by OCT after the surgery. Univariate analysis for group 1 and 2 revealed that intracameral injection of epinephrine during phacoemulsification was associated with the development of macular edema. In group 2, five patients (1.33%) developed cystoid macular edema. Statistically significant differences in the clinical course of CMT were observed at 2 months (201.2 ± 23.1, 250.0 ± 29.8, and 371.0 ± 160.3 in group 1, group 2A, and group 2B, respectively; p < 0.001) and 1 month postoperatively (198.5 ± 23.6, 237.8 ± 40.9, and 314.0 ± 104.5 in group 1, group 2A, and group 2B, respectively; p < 0.001). Group 2B required additional treatment and eventually achieved best-corrected visual acuity of >0.2 with CMT in the normal range. Conclusions The intracameral injection of epinephrine may cause macular edema after uncomplicated cataract surgery. Examination of CMT using OCT is recommended for the early detection of macular edema.

Objectives: To conduct a comparative study of children’s health in South Korea versus North Korea focusing on air pollution. Methods: We used annual mortality rate, prevalence, and environmental indicators data from the World Bank and World Health Organizations (WHO). Trend analysis of the two Koreas was conducted to evaluate changes in health status over time. Spearman’s correlation analysis was used to find out the correlation between environmental indicators and children’s health status. Results: We found a distinct gap in children’s health status between the two Koreas. While North Korea reported a higher death rate of children than South Korea, both showed a decreasing trend with the gap narrowing from 2000 to 2017. The prevalence of overweight and obesity increased and that of thinness decreased in both Koreas. Except PM2.5 exposure, South Korea reported higher figures in most indicators of air pollutant emissions (South Korea, mean (SD)=28.3 (2.0); North Korea, mean (SD)=36.5 (2.8), P-value=0.002). Conclusion This study empirically discovered the gaps and patterns of children’s health between South Korea and North Korea. North Korean children experienced more severe health outcomes than children in South Korea. These findings imply that epigenetic modification caused by environmental stressors affect children’s health in the two Koreas despite similar genetic characteristics. Considering the gaps in children’s health between the two Koreas, more attention and resources need to be directed towards North Korea because the necessary commodities and services to improve children’s health are lacking in North Korea.

Background/Aims: We evaluated the feasibility and long-term efficacy of the combination of cytarabine, idarubicin, and all-trans retinoic acid (ATRA) for treating patients with newly diagnosed acute promyelocytic leukemia (APL). Methods: We included 87 patients with newly diagnosed acute myeloid leukemia and a t(15;17) or promyelocytic leukemia/retinoic acid receptor alpha (PML-RARα) mutation. Patients received 12 mg/m2/day idarubicin intravenously for 3 days and 100 mg/m2/day cytarabine for 7 days, plus 45 mg/m2/day ATRA. Clinical outcomes included complete remission (CR), relapse-free survival (RFS), overall survival (OS), and the secondary malignancy incidence during a 20-year follow-up. Results: The CR, 10-year RFS, and 10-year OS rates were 89.7%, 94.1%, and 73.8%, respectively, for all patients. The 10-year OS rate was 100% for patients that achieved CR. Subjects were classified according to the white blood cell (WBC) count in peripheral blood at diagnosis (low-risk, WBC < 10,000/mm3; high-risk, WBC ≥ 10,000/mm3). The low-risk group had significantly higher RFS and OS rates than the high-risk group, but the outcomes were not superior to the current standard treatment (arsenic trioxide plus ATRA). Toxicities were similar to those observed with anthracycline plus ATRA, and higher than those observed with arsenic trioxide plus ATRA. The secondary malignancy incidence after APL treatment was 2.7%, among the 75 patients that achieved CR, and 5.0% among the 40 patients that survived more than 5 years after the APL diagnosis. Conclusions Adding cytarabine to anthracycline plus ATRA was not inferior to anthracycline plus ATRA alone, but it was not comparable to arsenic trioxide plus ATRA. The probability of secondary malignancy was low.

Purpose: We assessed prenatal detection rates of congenital heart disease (CHD) and associations between maternal serum biomarkers and non-chromosomal CHD in singleton pregnancies. Materials and Methods: This study was conducted as a secondary analysis of data obtained during a multicenter prospective cohort study that investigated the cost-effectiveness of prenatal testing for fetal aneuploidy. We analyzed the prenatal detection rate and accuracy for CHD screening via ultrasound during the second trimester, as well as associations between serum biomarkers and CHDs, in singleton newborns without chromosomal abnormalities. Results: Among 6715 women, 142 (2.1%) newborns were born with CHDs, of which 67 (1.0%) newborns had major CHDs. The prenatal detection rate for all CHDs and major CHDs were 34.5% and 58.2%, respectively. After excluding isolated ventricular septal defects, the detection rate for critical CHDs was 85.9%. Women with low pregnancy-associated plasma protein A (PAPP-A) (<0.4 multiples of the median, MOM) face increased risks of non-chromosomal CHDs [adjusted odds ratio (aOR) 2.76; 95% confidence interval (CI) 1.36–5.13] and major CHDs (aOR 7.30; 95% CI 3.18–15.59), compared to those without CHDs. A higher inhibin A level (≥2.5 MOM; aOR 4.84; 95% CI 1.42–12.46) was associated with non-chromosomal major CHDs. Conclusion Ultrasonography performed during the second trimester by obstetricians detected over 85% of critical CHDs. Low maternal serum PAPP-A or high inhibin-A was associated with non-chromosomal CHDs. These results may contribute to an improvement in prenatal diagnosis of CHDs.

Purpose: To investigate the biometric characteristics of eyes with pseudoexfoliation syndrome (PEX) according to the anterior chamber depth (ACD) by comparing them to patients with acute angle closure (AAC) and a control group. Methods: A total of 130 eyes of 121 subjects (PEX, 49 eyes; AAC, 28 eyes; and control, 53 eyes) were included in the study. Axial length (AL), ACD, and lens thickness (LT) were measured with an IOL Master® 700 (Carl Zeiss Meditec, Jena, Germany). The total PEX (PXall) group was divided into a PEX with deep ACD group (PXd) and a shallow ACD group (PXs) based on an ACD of 2.70 mm. We compared the biometric results among the PXall, PXd, PXs, AAC, and control groups. Results: There was no significant difference in AL between the PXall and control groups; however, the PXall group had a shallower ACD and thicker lenses. After dividing the PXall group into two groups based on ACD, the PXd group showed no difference in LT compared to the control group (p = 0.113). The LT of the PXs group was thicker than those of the PXd and control groups (p < 0.001 and p < 0.001, respectively). The PXs group had longer ALs than the AAC group (p = 0.025); however, there was no difference in LT or in the ratio of LT to AL (p = 0.222 and p = 0.076, respectively). Conclusions The biometric characteristics were different in eyes with PEX based on ACD. PEX patients with deep ACDs showed no difference in biometry compared to the control group; however, PEX patients with shallow ACDs showed characteristics of a thick LT, similar to AAC patients. There was no difference in the ratio of LT to AL among groups.

Background/Aims: In Korea, medications are available by prescription from a physician, or can be purchased over-the-counter (OTC) without a prescription. Education regarding both prescribed and OTC drugs is important to minimize side effects and avoid drug abuse. The risk of side effects due to polypharmacy is increasing due to the growing number of elderly patients with comorbidities. Methods: There are various clinical guidelines for physicians, but it is difficult for patients and their caregivers to find published guidelines regarding drug use. In this regard, experts from nine subspecialties of internal medicine, geriatric medicine, and guideline development methodology formed a working group to develop guidelines for safe drug use under the Clinical Practice Guidelines Committee of the Korean Association of Internal Medicine. Results: The main contents of this guideline are 1) safe and effective drug administration, 2) the proper use of analgesics (acetaminophen and nonsteroidal anti-inflammatory drugs), 3) the proper use of tranquilizers and sleeping pills to prevent drug abuse, 4) points to be aware of when taking multiple medications. Conclusions The guidelines were developed for patients and their caregivers to understand the general principles and precautions for drug use, including commonly used painkillers, mood stabilizers, sleeping pills, and polypharmacy. These guidelines could also be used as educational materials for physicians, nurses, and healthcare workers to educate patients and their caregivers.

Background/Aims: In Korea, medications are available by prescription from a physician, or can be purchased over-the-counter (OTC) without a prescription. Education regarding both prescribed and OTC drugs is important to minimize side effects and avoid drug abuse. The risk of side effects due to polypharmacy is increasing due to the growing number of elderly patients with comorbidities. Methods: There are various clinical guidelines for physicians, but it is difficult for patients and their caregivers to find published guidelines regarding drug use. In this regard, experts from nine subspecialties of internal medicine, geriatric medicine, and guideline development methodology formed a working group to develop guidelines for safe drug use under the Clinical Practice Guidelines Committee of the Korean Association of Internal Medicine. Results: The main contents of this guideline are 1) safe and effective drug administration, 2) the proper use of analgesics (acetaminophen and nonsteroidal anti-inflammatory drugs), 3) the proper use of tranquilizers and sleeping pills to prevent drug abuse, 4) points to be aware of when taking multiple medications. Conclusions The guidelines were developed for patients and their caregivers to understand the general principles and precautions for drug use, including commonly used painkillers, mood stabilizers, sleeping pills, and polypharmacy. These guidelines could also be used as educational materials for physicians, nurses, and healthcare workers to educate patients and their caregivers.