Clinical and Radiological Features of Korean Patients With Anti-HMGCR Myopathy

Background@#and Purpose To understand the characteristics of Korean patients with anti-3-hydroxy-3-methylglutaryl-coenxyme A reductase (HMGCR) myopathy, we measured antiHMGCR antibodies and analyzed the clinical, radiological, and pathological features of patients with anti-HMGCR myopathy. @*Methods@#We measured titers of anti-HMGCR antibodies in the sera of 99 patients with inflammatory myopathy, 36 patients with genetic myopathy, and 63 healthy subjects using an enzyme-linked immunosorbent assay. We tested 16 myositis-specific autoantibodies (MSAs) in all patients with anti-HMGCR myopathy. @*Results@#Positivity for the anti-HMGCR antibody was observed in 17 (4 males and 13 females) of 99 patients with inflammatory myopathy. The median age at symptom onset was 60 years.Ten (59%) of the patients with anti-HMGCR positivity had taken statins. The titer of antiHMGCR antibodies was significantly higher in the statin-naïve group (median=230 U/mL, interquartile range=170–443 U/mL) than in the statin-exposed group (median=178 U/mL, interquartile range=105–210 U/mL, p=0.045). The most common symptom was proximal muscle weakness in 15 patients (88%), followed by myalgia in 9 (53%), neck weakness in 4 (24%), dysphagia in 3 (18%), and skin lesions in 2 (12%). The median titer of anti-HMGCR antibody was 202 U/mL. We found eight different MSAs in nine (53%) patients. The median disease duration from symptom onset to diagnosis was significantly shorter in the MSA-positive group than in the MSA-negative group (p=0.027). @*Conclusions@#Our study was the first to measure anti-HMGCR antibodies in inflammatory myopathy. It has provided new findings, including the suggestion of the coexistence of other MSAs in Korean patients.

Transition Substitution of Desired Bases in Human Pluripotent Stem Cells with Base Editors: A Step-by-Step Guide

The recent advances in human pluripotent stem cells (hPSCs) enable to precisely edit the desired bases in hPSCs to be used for the establishment of isogenic disease models and autologous ex vivo cell therapy. The knock-in approach based on the homologous directed repair with Cas9 endonuclease, causing DNA double-strand breaks (DSBs), produces not only insertion and deletion (indel) mutations but also deleterious large deletions. On the contrary, due to the lack of Cas9 endonuclease activity, base editors (BEs) such as adenine base editor (ABE) and cytosine base editor (CBE) allow precise base substitution by conjugated deaminase activity, free from DSB formation. Despite the limitation of BEs in transition substitution, precise base editing by BEs with no massive off-targets is suggested to be a prospective alternative in hPSCs for clinical applications. Considering the unique cellular characteristics of hPSCs, a few points should be considered. Herein, we describe an updated and optimized protocol for base editing in hPSCs. We also describe an improved methodology for CBE-based C to T substitutions, which are generally lower than A to G substitutions in hPSCs.

Role of non‑pulmonary vein triggers in persistent atrial fibrillation

Pulmonary vein isolation is an well-established treatment strategy for atrial fibrillation (AF), and it is especially effective for patients with paroxysmal AF. However, the success rate is limited for patients with persistent AF, because non-pul‑ monary vein triggers which increase AF recurrence are frequently found in these patients. The major non-pulmonary vein triggers are from the left atrial posterior wall, left atrial appendage, ligament of Marshall, coronary sinus, superior vena cava, and crista terminalis, but other atrial sites can also generate AF triggers. All these sites have been known to contain atrial myocytes with potential arrhythmogenic electrical activity. The prevalence and clinical characteristics of these non-pulmonary vein triggers are well studied; however, the clinical outcome of catheter ablation for persistent AF is still unclear. Here, we reviewed the current ablation strategies for persistent AF and the clinical implications of major non-pulmonary vein triggers.

Comparison of Programmed Cell Death Ligand 1Status between Core Needle Biopsy and Surgical Specimens of Triple-Negative Breast Cancer

Purpose@#Pembrolizumab is currently used to treat advanced triple-negative breast cancer (TNBC) and high-risk early TNBC with neoadjuvant chemotherapy (NAC). The tumor-infiltrating lymphocyte (TIL) level and programmed cell death ligand 1 (PDL1) status are predictors of response to NAC and immune checkpoint inhibitor treatment. We aimed to investigate whether the PD-L1 status in core needle biopsies (CNBs) could represent the whole tumor in TNBC. @*Materials and Methods@#A total of 49 patients diagnosed with TNBC who received upfront surgery without NAC between January 2018 and March 2021 were included. The PD-L1 expression (SP142 and 22C3 clones) and TIL were evaluated in paired CNBs and resected specimens. The concordance PD-L1 status and TIL levels between CNBs and resected specimens were analyzed. @*Results@#PD-L1 positivity was more frequently observed in resected specimens. The overall reliability of TIL level in the CNB was good [intraclass correlation coefficient (ICC)=0.847, p<0.001]. The agreements of PD-L1 status were good and fair, respectively (SP142, κ=0.503, p<0.001; 22C3, κ=0.380, p=0.010). As the core number of CNB increased, the reliability and agreement also improved, especially from five tumor cores (TIL, ICC=0.911, p<0.001; PD-L1 [22C3], κ=0.750, p=0.028). Regarding PD-L1 (SP142), no further improvement was observed with ≥5 tumor cores (κ=0.600, p=0.058). @*Conclusion@#CNBs with ≥5 tumor cores were sufficient to represent the TIL level and PD-L1 (22C3) status in TNBC.

Clinicopathological Characteristics of NRG1 Fusion–Positive Solid Tumors in Korean Patients / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Neuregulin 1 (NRG1) gene fusion is a potentially actionable oncogenic driver. The oncoprotein binds to ERBB3-ERBB2 heterodimers and activates downstream signaling, supporting a therapeutic approach for inhibiting ERBB3/ERBB2. However, the frequency and clinicopathological features of solid tumors harboring NRG1 fusions in Korean patients remain largely unknown. @*Materials and Methods@#We reviewed archival data from next-generation sequencing panel tests conducted at a single institution, specifically selecting patients with in-frame fusions that preserved the functional domain. The clinicopathological characteristics of patients harboring NRG1 fusions were retrospectively reviewed. @*Results@#Out of 8,148 patients, NRG1 fusions were identified in 22 patients (0.27%). The average age of the patients was 59 years (range, 32 to 78 years), and the male-to-female ratio was 1:1.2. The lung was the most frequently observed primary site (n=13), followed by the pancreaticobiliary tract (n=3), gastrointestinal tract (n=2, stomach and rectum each), ovary (n=2), breast (n=1), and soft tissue (n=1). Histologically, all tumors demonstrated adenocarcinoma histology, with the exception of one case of sarcoma. CD74 (n=8) and SLC3A2 (n=4) were the most frequently identified fusion partners. Dominant features included the presence of fewer than three co-occurring genetic alterations, a low tumor mutation burden, and low programmed death-ligand 1 expression. Various clinical responses were observed in patients with NRG1 fusions. @*Conclusion@#Despite the rarity of NRG1 fusions in Korean patients with solid tumors, identification through next-generation sequencing enables the possibility of new targeted therapies.

Clinicopathological differences in radiation-induced organizing hematomas of the brain based on type of radiation treatment and primary lesions

Background@#Radiation-induced organizing hematoma (RIOH) is a sporadic form of cavernous hemangioma (CH) that occurs after cerebral radiation. RIOH lesions are distinct histologically from de novo CH; however, detailed research on this subject is lacking. In the present study, the clinical and histological features of RIOHs were evaluated based on causative lesions. @*Methods@#The present study included 37 RIOHs confirmed by surgical excision from January 2009, to May 2020, in Yonsei Severance Hospital. All cases were divided into subgroups based on type of radiation treatment (gamma knife surgery [GKS], n = 24 vs. conventional radiation therapy [RT], n = 13) and pathology of the original lesion (arteriovenous malformation, n = 14; glioma, n = 12; metastasis, n = 4; other tumors, n = 7). The clinicopathological results were compared between the groups. @*Results@#Clinical data of multiplicity, latency, and size and wall thickness of the original tumors and RIOHs were analyzed. The GKS group showed shorter latency (5.85 ± 4.06 years vs. 11.15 ± 8.27 years, p = .046) and thicker tumor wall (693.7 ± 565.7 μm vs. 406.9 ± 519.7 μm, p = .049) than the conventional RT group. Significant difference was not found based on original pathology. @*Conclusions@#RIOH is more likely to occur earlier with thick tumor wall in subjects who underwent GKS than in patients who underwent conventional RT. These results indicate the clinical course of RIOH differs based on type of treatment and might help determine the duration of follow-up.

Closed extensor tendon rupture caused by Kienböck disease: a case report

Kienböck disease, a rare disease that can cause chronic pain and motor dysfunction, occurs due to avascular necrosis of the lunate bone, which leads to dislocation of the carpal bone. Among various other etiologies, Kienböck disease can cause closed tendon rupture of the finger. In this report, we introduce a case of total rupture of the second extensor digitorum communis and the extensor indicis proprius tendons caused by undiagnosed Kienböck disease in an elderly female patient.

Prevalence and Characteristics of Atrial Tachycardia From Noncoronary Aortic Cusp During Atrial Fibrillation Catheter Ablation

Background and Objectives@#Atrial tachycardias (ATs) from noncoronary aortic cusp (NCC) uncovered after radiofrequency ablation for atrial fibrillation (AF) are rarely reported. This study was conducted to investigate the prevalence and clinical characteristics of NCC ATs detected during AF ablation and compare their characteristics with de novo NCC ATs without AF. @*Methods@#Consecutive patients who underwent radiofrequency catheter ablation for AF were reviewed from the multicenter AF ablation registry of 11 tertiary hospitals. The clinical and electrophysiological characteristics of NCC AT newly detected during AF ablation were compared with its comparators (de novo NCC AT ablation cases without AF). @*Results@#Among 10,178 AF cases, including 1,301 redo ablation cases, 8 (0.08%) NCC AT cases were discovered after pulmonary vein isolation (PVI; 0.07% in first ablation and 0.15% in redo ablation cases). All ATs were reproducibly inducible spontaneously or with programmed atrial stimulation without isoproterenol infusion. The P-wave morphological features of tachycardia were variable depending on the case, and most cases exhibited 1:1 atrioventricular conduction. AF recurrence rate after PVI and NCC AT successful ablation was 12.5% (1 of 8). Tachycardia cycle length was shorter than that of 17 de novo ATs from NCC (303 versus 378, p=0.012). No AV block occurred during and after successful AT ablation. @*Conclusions@#Uncommon NCC ATs (0.08% in AF ablation cases) uncovered after PVI, showing different characteristics compared to de-novo NCC ATs, should be suspected irrespective of P-wave morphologies when AT shows broad propagation from the anterior interatrial septum.

Differential Diagnosis of Thick Myocardium according to Histologic Features Revealed by Multiparametric Cardiac Magnetic Resonance Imaging

Left ventricular (LV) wall thickening, or LV hypertrophy (LVH), is common and occurs in diverse conditions including hypertrophic cardiomyopathy (HCM), hypertensive heart disease, aortic valve stenosis, lysosomal storage disorders, cardiac amyloidosis, mitochondrial cardiomyopathy, sarcoidosis and athlete’s heart. Cardiac magnetic resonance (CMR) imaging provides various tissue contrasts and characteristics that reflect histological changes in the myocardium, such as cellular hypertrophy, cardiomyocyte disarray, interstitial fibrosis, extracellular accumulation of insoluble proteins, intracellular accumulation of fat, and intracellular vacuolar changes. Therefore, CMR imaging may be beneficial in establishing a differential diagnosis of LVH. Although various diseases share LV wall thickening as a common feature, the histologic changes that underscore each disease are distinct.This review focuses on CMR multiparametric myocardial analysis, which may provide clues for the differentiation of thickened myocardium based on the histologic features of HCM and its phenocopies.

Iatrogenic Spark Burn Injury to the Chest From a Transcutaneous Pacing Patch

Iatrogenic electrical burns that occur from the use of a defibrillator, a paddle-type cardiac shock device, have been reported in various forms. Electrical burns are usually conducted directly through the skin and are more damaging than scald burns or contact burns. A transcutaneous cardiac pacing device is a patch-type cardiac shock device that automatically delivers a shock when an abnormal heart rhythm is detected. We introduce a unique case of iatrogenic electrical burns caused by the transcutaneous pacing patch of a cardiac shock device. Electrical energy was converted into a spark due to foreign bodies deposited around the patch, resulting in damage to the peripheral area of the skin.

Left atrial wall thickness and its relationship with reconnection after pulmonary vein isolation in patients with atrial fibrillation evaluated using a three‑dimensional wall thickness map

Background@#The major cause of recurrence after pulmonary vein (PV) isolation for atrial fibrillation (AF) is PV recon‑ nection, and thicker wall could be associated with reconnection. @*Objectives@#This study aimed to evaluate the wall thickness of the PV antrum in reconnection sites using a threedimensional (3D) wall thickness map. @*Methods@#A total of 91 patients who underwent a second ablation procedure due to AF recurrence were evalu‑ ated. The locations of the PV reconnection sites were confirmed in electroanatomical maps. A 3D atrial wall thickness (AWT) map was created using computed tomography scan data. The AWT values of the ablation lines of the index procedure were graded in each segment of the PV antrum: grade 1, 0.5 2.5 mm. @*Results@#A total of 281 PV reconnection sites among 1256 segments of the PV antrum in 79 patients were detected. The average AWT grades were 2.7 ± 1.0 and 2.2 ± 1.0 in the reconnected and non-reconnected segments, respectively (P < 0.01). Higher AWT grades were observed in the reconnected superior segments of the left superior PV, carina and inferior segments of the left inferior PV, superior and posterior segments of the right superior PV, and posterior and inferior segments of the right inferior PV. @*Conclusion@#The reconnected segments of the PV antrum showed thicker myocardium than the non-reconnected ones in patients with recurrent AF after catheter ablation. A wall thickness map for PV isolation could be considered for customized ablation in order to reduce PV reconnection.

A propeller superficial transverse cervical artery perforator flap for defect coverage of the submental area: a case report

Reconstruction of submental defects is a challenge that needs to be approached carefully, since many important anatomical structures are located in this small space. Both aesthetic and functional outcomes should be considered during reconstruction. In this report, we describe a case where a superficial branch of the transverse cervical artery (STCA) perforator propeller flap was applied for coverage of the submental area. An 85-year-old woman presented with a 3-cm ovoid mass on her submental area. We covered the large submental defect with a STCA rotational flap in a 180° propeller pattern. The flap survived well without any complications at 1 year of follow-up. A STCA propeller flap is a useful surgical option in reconstruction for defect coverage of the submental area.

Comparative occurrence of ischemic stroke with the rhythm versus rate control strategy in a national prospective cohort of atrial fibrillation

Background/Aims@#Comparative occurrence of ischemic stroke for rhythm versus rate control strategy in patients with non-valvular atrial fibrillation (NVAF) is still inconclusive. The purpose of this study was to investigate whether the rhythm control strategy is associated with a lower risk of ischemic stroke compared to the rate control strategy in NVAF patients. @*Methods@#The CODE-AF registry prospectively enrolled 6,280 consecutive patients who were treated for NVAF at 10 tertiary referral centers in South Korea. Of these, 2,513 NVAF patients (age, 67 ± 10 years; male, 61.8%) were clinically followed up for over 1-year and divided into rate and rhythm control groups. @*Results@#Those treated with the rhythm control strategy were younger and had less proportions of underlying disease compared to those treated with the rate control strategy. After the propensity matching analysis, those treated with the rhythm control strategy had similar baseline characteristics including the CHA 2 DS 2 -VASC score compared to those treated with the rate control strategy.The rate of oral anticoagulation, all bleeding, and hospitalization were also similarly between the two groups. The incidence rate of ischemic stroke in the rhythm control group was significantly lower than in the rate control group (0.7 vs. 6.9 per 1,000 person-years, p = 0.011). @*Conclusions@#The rhythm control strategy demonstrated a beneficial effect to lower the risk of ischemic stroke during a 1-year follow-up compared to the rate control strategy.

Biomarkers and diagnostic tools for lung cancer

Lung cancer is the leading cause of cancer-related deaths in developing to advanced countries worldwide. The incidence rate of lung cancer in Korea has been increasing steadily since 1997. Statistics show that in 2017 alone, the incidence and mortality rates for lung cancer were 52.7 and 34.8 per 100,000 people, respectively, accounting for the highest cause of cancer death in Korea. The process of accurately diagnosing lung cancer consists of several steps, starting with the discovery of pulmonary nodule(s) via a cancer screening test or various other methods followed by the collection of cells or tissues and the identification of target molecules. Thereafter, staging and the development of a therapeutic plan lead to improved clinical outcomes. After the completion of a pilot study, a nationwide lung cancer screening program was introduced in Korea; since 2019, this program has targeted population at high risk for lung cancer: men and women aged 54 to 74 years who had a smoking history of 30 pack-years or more. The frequency of detection of pulmonary nodules is increasing in proportion to the public interest in health and economic growth.In this review, we present diagnostic techniques and biomarkers that are widely used in the medical field in the hope that such information would benefit clinical practice.

The 2021 Korean Heart Rhythm Society Guidelines for a New Approach and Integrated Management of Atrial Fibrillation / 대한내과학회지

The prevalence of atrial fibrillation (AF) is gradually increasing with the aging of the population, and there is also increasing interest in AF with the development of various single-lead electrocardiography measurement methods for diagnosis. Further, the current diagnosis and treatment policies for AF do not reflect its progression and complexity. In addition, the various factors related to AF diagnosis and treatment are not simple due to the diversification of tools, advances in treatment methods, and complex mechanism of AF. Therefore, there are many challenges to developing a simple AF classification system. To overcome these, there have been a number of attempts to systematically characterize AF according to treatment and prognosis rather than using a uniform classification. Further, as mentioned in the previous AF guidelines, further research is being conducted on an integrated patient–physician approach to AF. Such an approach would be the basis for consistent treatment based on the guidelines, and would help to improve patient outcomes. Further, for the integrated management of AF patients, some changes should be made to the current approach to develop a multidisciplinary approach, including changes to the behavior of team members, patients, their family members, and physicians. The Korean Heart Rhythm will introduce an integrated approach to the classification and structure of AF management, and provide guidelines for its application in clinical practice.

Tailored stereotactic radiotherapy technique using deep inspiration breath-hold to reduce stomach dose for cardiac radioablation

Purpose@#To provide a new insight on a novel safe cardiac radioablation using deep inspiration breath-hold (DIBH) to reduce gastrointestinal dose. @*Materials and Methods@#For treating incessant ventricular tachycardia (VT) originated from left ventricle inferior scar abutting the stomach, a target delineation and treatment planning for cardiac radioablation was performed. With four different computed tomography (CT) scan protocols—DIBH, full expiration breath-hold, four-dimensional (4D) CT without and with abdominal compression, the distances between the target and the stomach were compared. @*Results@#Among the protocols, the CT scan with DIBH showed largest distance between the target and the stomach and selected for the treatment planning. The prescribed dose was 25 Gy in a single fraction, and satisfactory dosimetric parameters were achieved with the DIBH. The patient was successfully treated with the DIBH, and experienced no acute toxicity. @*Conclusion@#To gain the best benefit from cardiac radioablation, understanding the possible toxicity in the adjacent organs is crucial. By moving the heart with thoraco-diaphragmatic movement by DIBH, the target could be physically separated from the stomach.

Tailored stereotactic radiotherapy technique using deep inspiration breath-hold to reduce stomach dose for cardiac radioablation

Purpose@#To provide a new insight on a novel safe cardiac radioablation using deep inspiration breath-hold (DIBH) to reduce gastrointestinal dose. @*Materials and Methods@#For treating incessant ventricular tachycardia (VT) originated from left ventricle inferior scar abutting the stomach, a target delineation and treatment planning for cardiac radioablation was performed. With four different computed tomography (CT) scan protocols—DIBH, full expiration breath-hold, four-dimensional (4D) CT without and with abdominal compression, the distances between the target and the stomach were compared. @*Results@#Among the protocols, the CT scan with DIBH showed largest distance between the target and the stomach and selected for the treatment planning. The prescribed dose was 25 Gy in a single fraction, and satisfactory dosimetric parameters were achieved with the DIBH. The patient was successfully treated with the DIBH, and experienced no acute toxicity. @*Conclusion@#To gain the best benefit from cardiac radioablation, understanding the possible toxicity in the adjacent organs is crucial. By moving the heart with thoraco-diaphragmatic movement by DIBH, the target could be physically separated from the stomach.

Expression and Role of Epithelial Membrane Proteins in Tumorigenesis of Hormone Receptor-Positive Breast Cancer / 한국유방암학회지

Purpose@#Studies on the expression of epithelial membrane proteins (EMPs) in breast cancer have been rare and limited. In the present study, we aimed to evaluate the expression of EMP1, EMP2, and EMP3 in invasive ductal carcinoma (IDC) of the breast, and investigate their clinical implications. @*Methods@#In total, 418 IDC cases were collected, and specimens were used to construct a tissue microarray. Immunohistochemical staining of EMP1, EMP2, and EMP3 was performed and the results were analyzed in combination with the clinical data. @*Results@#EMP1 was expressed in > 90% of all IDC subtypes. A decreased expression of EMP2 and EMP3 was observed in triple-negative breast cancer. EMP3 expression was independently associated with human epidermal growth factor receptor 2 (HER2) positivity. HER2-negative cases exhibited a decreased EMP2 expression along with a higher histological grade and an increased proliferative index. No significant difference was found in the overall survival or disease-free survival based on the EMP expression. In HER2-negative breast cancer, EMP2 expression inversely correlated with the histological grade and proliferative index. @*Conclusion@#EMP2 may be involved in the early stage of tumor development in hormonepositive breast cancer.

Differentiation of the right versus left outflow tract ventricular arrhythmias using local activation time at the His bundle electrogram

Background@#Although multiple algorithms based on surface electrocardiographic criteria have been introduced to localize idiopathic ventricular arrhythmia (VA) origins from the outflow tract (OT), their diagnostic accuracy and clini‑ cal usefulness remain limited. We evaluated whether local activation time of the His bundle region could differentiate left and right ventricular OT VA origins in the early stage of electrophysiology study. @*Methods@#We studied 30 patients who underwent catheter ablation for OT VAs with a left bundle branch block pat‑ tern and inferior axis QRS morphology. The interval between the local V signal on the mapping catheter placed in the RVOT and His bundle region (V(RVOT)-V(HB) interval) and the interval from QRS complex onset to the local V signal on the His bundle region (QRS-V(HB) interval) were measured during VAs. @*Results@#The V(RVOT)-V(HB) and QRS-V(HB) intervals were significantly shorter in patients with LVOT VAs. The area under the curve (AUC) for the V(RVOT)-V(HB) interval by receiver operating characteristic analysis was 0.865. A cutoff value of ≤ 50 ms predicted an LVOT origin of VA with sensitivity, specificity, and positive and negative predictive values of 100%, 62.5%, 40%, and 100%, respectively. The QRS-V(HB) interval showed similar diagnostic accuracy (AUC, 0.840), and a cutoff value of ≤ 15 ms predicted an LVOT origin of VA with a sensitivity, specificity, and positive and negative predictive values of 100%, 70.8%, 45.2%, and 100%, respectively. @*Conclusion@#The V(RVOT)-V(HB) and QRS-V(HB) intervals could differentiate left from right OT origins of VA with high sensitivity and negative predictive values.

Correlation of PD-L1 Expression Tested by 22C3 and SP263 in Non-Small Cell Lung Cancer and Its Prognostic Effect on EGFR Mutation–Positive Lung Adenocarcinoma / 결핵및호흡기질환

BACKGROUND@#Programmed death-ligand 1 (PD-L1) expression is tested by immunohistochemistry (IHC)—22C3, SP263, and SP142. The aim of this study is to evaluate the correlation among the three methods of PD-L1 IHC in non-small cell lung cancer (NSCLC) and clinical significance of PD-L1 expression in lung adenocarcinoma with an epidermal growth factor receptor (EGFR)–tyrosine kinase domain mutation.@*METHODS@#The results of 230 patients who were pathologically confirmed as having NSCLC; tested using PD-L1 IHC 22C3, SP263, and SP142 methods; and evaluated via the peptide nucleic acid clamping method to confirm EGFR mutation, were analyzed in this study.@*RESULTS@#164 patients underwent both the SP263 and 22C3 tests. There was a significant positive correlation between the outcomes of the two tests (Spearman correlation coefficient=0.912, p<0.001), with a derived regression equation as follows: 22C3=15.2+0.884×SP263 (R2=0.792, p<0.001). There was no relationship between the expression of PD-L1 and clinical parameters, including EGFR–tyrosine kinase inhibitor (TKI) mutation. The PD-L1 expression in patients treated with EGFR-TKI yielded a 2-month-shorter progression period than that in the PD-L1–negative group. However, this did not reach statistical significance (PD-L1<1% vs. PD-L1≥1%, 10 months vs. 8 months).@*CONCLUSION@#The results of the 22C3 and those of SP263 methods were in good correlation with one another. Since the PD-L1 expression is not influenced by the EGFR mutation, it is necessary to perform a PD-L1 test to set the treatment direction in the patients with EGFR-mutant NSCLC.