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Abstract Background Lazertinib is an oral, third‐generation EGFR‐TKI, which specifically targets the EGFR T790M mutation along with activating mutations Ex19del and L858R. More real‐world data are needed to evaluate its efficacy and safety in treating locally advanced and metastatic non‐small cell lung cancer (NSCLC) following prior EGFR TKI treatment. Methods This multicenter retrospective study was conducted at seven university hospitals affiliated to the Catholic Medical Center (CMC) in Korea. A clinical data warehouse (CDW) platform was used to access and extract information. Results A total of 48 patients were assessed. The majority were female (75%) and diagnosed with adenocarcinoma (95.8%). All patients had the EGFR mutation at diagnosis, 27 (56.3%) had the exon 19 deletion, 20 (41.7%) had the L858R mutation, and one (2.0%) had the exon 18 mutation. The median progression‐free survival (PFS) was 15.4 months. At 6, 12, and 18 months, PFS rates were 79.1%, 53.6%, and 27.3%, respectively. When PFS was analyzed by prior TKI duration (18 months), significant differences were noted at the 6 and 9‐month mark (p = 0.013 and p = 0.010, respectively). In multivariate analysis for PFS, only prior TKI duration and ECOG score showed statistical significance (p = 0.026 and p = 0.049, respectively). In the multivariate analysis for OS, ECOG score showed statistical significance (p = 0.006). Among 48 patients, 34 (70.8%) experienced adverse events (AEs) related to lazertinib. The most frequent AEs were skin reaction (29.8%), diarrhea (21.3%), and peripheral neuropathy (20.8%). Conclusions The results suggest that lazertinib is effective in second or more line settings, with tolerable safety profile. More patient data are necessary to find possible prognostic markers associated with patient outcome.

Background: Many patients with lung cancer have underlying chronic lung diseases. We assume that baseline lung functions might also affect the prognosis of non-small cell lung cancer (NSCLC) patients receiving immunotherapy. Objectives: We aimed to assess the impact of pretreatment clinical parameters, including lung function measures such as forced vital capacity (FVC), on the prognosis of patients with NSCLC following immune checkpoint inhibitors (ICIs) therapy. Design: Retrospective multicenter study. Methods: Study subjects were consecutively selected from a multicenter cohort of patients with NSCLC who were undergoing immunotherapy. Patients were selected regardless of their initial cancer stage and prior treatment. The primary outcome was immunotherapy-related overall survival (iOS), defined as the duration from the initiation of immunotherapy to the time patients were censored. Spirometry values were acquired before bronchodilator application and were performed within the year before the first ICI treatment Results: We selected 289 patients for evaluation. The median iOS was 10.9 months (95% confidence interval (CI), 7.5–14.3). Programmed death-ligand 1 (PD-L1) expression, tested by SP263, was

Abstract Patient-derived organoids (PDOs) are valuable in predicting response to cancer therapy. PDOs are ideal models for precision oncologists. However, their practical application in guiding timely clinical decisions remains challenging. This study focused on patients with advanced EGFR-mutated non-small cell lung cancer and employed a cancer organoid-based diagnosis reactivity prediction (CODRP)-based precision oncology platform to assess the efficacy of EGFR inhibitor treatments. CODRP was employed to evaluate EGFR-tyrosine kinase inhibitors (TKI) drug sensitivity. The results were compared to those obtained using area under the curve index. This study validated this index by testing lung cancer-derived organoids in 14 patients with lung cancer. The CODRP index-based drug sensitivity test reliably classified patient responses to EGFR-TKI treatment within a clinically suitable 10-day timeline, which aligned with clinical drug treatment responses. This approach is promising for predicting and analyzing the efficacy of anticancer, ultimately contributing to the development of a precision medicine platform.

Abstract Introduction Men with African ancestry have the highest incidence and mortality rates of prostate cancer (PCa) worldwide. Methods This study aimed to identify differentially methylated genes between tumor vs. adjacent normal and aggressive vs. indolent PCa in 121 African American patients. Epigenome‐wide DNA methylation patterns in tumor DNA were assessed using the human Illumina Methylation EPIC V1 array. Results Around 5,139 differentially methylated CpG‐sites (q 0.2) were identified when comparing normal vs. tumor, with an overall trend of hypermethylation in prostate tumors. Multiple representative differentially methylated regions (DMRs), including immune‐related genes, such as CD40, Galectin3, OX40L, and STING, were detected in prostate tumors when compared to adjacent normal tissues. Based on an epigenetic clock model, we observed that tumors’ total number of stem cell divisions and the stem cell division rate were significantly higher than adjacent normal tissues. Regarding PCa aggressiveness, 2,061 differentially methylated CpG‐sites (q .05) were identified when the grade group (GG)1 was compared with GG4/5. Among these 2,061 CpG sites, 155 probes were consistently significant in more than one comparison. Among these genes, several immune system genes, such as COL18A1, S100A2, ITGA4, HLA‐C, and ADCYAP1, have previously been linked to tumor progression in PCa. Conclusion Several differentially methylated genes involved in immune‐oncologic pathways associated with disease risk or aggressiveness were identified. In addition, 261 African American‐specific differentially methylated genes related to the risk of PCa were identified. These results can shedlight on potential mechanisms contributing to PCa disparities in the African American Population.

Background: Lung cancer, especially non-small cell lung cancer (NSCLC), poses a significant health challenge globally due to its high mortality. Afatinib, a second-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), has shown superior efficacy over traditional chemotherapy in NSCLC treatment. However, issues like secondary resistance and adverse effects call for alternative therapies. HAD-B1, comprising 4 herbal medicines, has shown promise in lung cancer treatment in both preclinical and clinical settings. This study assesses the combination of HAD-B1 and Afatinib in advanced NSCLC patients to potentially improve outcomes by addressing the limitations of current EGFR-TKI therapies. Method: A randomized, open-label trial evaluated the efficacy and safety of HAD-B1 with Afatinib in 90 EGFR-mutation-positive NSCLC patients. Participants were divided into treatment and control groups, receiving Afatinib with or without HAD-B1. The study focused on the initial dose maintenance rate and disease control rate (DCR) of Afatinib, alongside secondary outcomes like survival rates and quality of life, under continuous safety monitoring. Results: Among the 90 participants, no significant difference was found in initial dose maintenance (60.98% in the treatment group vs 52.50% in the control, P = .4414) or DCR (80.49% vs 90.00%, P = .2283). Secondary outcomes like PFS, TTP, and OS showed no notable differences. However, physical functioning significantly improved in the treatment group ( P = .0475, PPS group). The control group experienced higher rates of adverse events of special interest and adverse drug reactions ( P = .01), suggesting HAD-B1 with Afatinib might enhance physical function without increasing adverse effects. Conclusion: Combining HAD-B1 with Afatinib potentially improves quality of life and reduces adverse events in advanced NSCLC patients. Further research is necessary to confirm the long-term benefits of this combination therapy, aiming to advance NSCLC treatment outcomes. Trial registration: Clinical Research Information Service (CRIS) of the Republic of Korea, https://cris.nih.go.kr/ (ID: KCT0005414).

Abstract Background About 3%–5% of non‐small cell lung cancer (NSCLC) presents positive anaplastic lymphoma kinase (ALK). Recently, several target agents have been approved as a treatment for ALK‐positive NSCLC. This study aimed to analyze the real‐world efficacy and outcome when administered crizotinib, the first approved target agent for ALK‐positive NSCLC, according to first‐ or late‐line treatment. Methods A total of 290 patients with ALK‐positive advanced NSCLC who were treated with crizotinib in 15 institutions in South Korea from January 2009 to December 2018 were enrolled. Results The median age of patients was 57.0 years, and 50.3% were male. The median follow‐up duration was 29.3 months. Among them, 113 patients received crizotinib as first‐line therapy. The objective response rate (ORR) was 60.1% (57.0% for first‐line recipients, 61.8% for second−/later‐line). Median (95% CI) progression‐free survival (PFS) was 13.7 (11.6–17.0) months. For first‐line recipients, overall survival (OS) was 26.3 (17.6–35.0) months. No significant difference in ORR, PFS and OS, according to the setting of crizotinib initiation, was observed. In a multivariate Cox regression analysis, old age, male gender, initially metastatic, and number of metastatic organs were associated with poor PFS and OS. The most common adverse events were nausea and vomiting, and severe adverse event leading to dose adjustment was hepatotoxicity. Conclusions ORR, PFS, OS, and adverse event profiles were comparable to previous clinical trials. Our findings could aid in the efficient management of ALK‐positive lung cancer patients.

Abstract Background Recently, cancer organoid-based drug sensitivity tests have been studied to predict patient responses to anticancer drugs. The area under curve (AUC) or IC50 value of the dose-response curve (DRC) is used to differentiate between sensitive and resistant patient‘s groups. This study proposes a multi-parameter analysis method (cancer organoid-based diagnosis reactivity prediction, CODRP) that considers the cancer stage and cancer cell growth rate, which represent the severity of cancer patients, in the sensitivity test. Methods On the CODRP platform, patient-derived organoids (PDOs) that recapitulate patients with lung cancer were implemented by applying a mechanical dissociation method capable of high yields and proliferation rates. A disposable nozzle-type cell spotter with efficient high-throughput screening (HTS) has also been developed to dispense a very small number of cells due to limited patient cells. A drug sensitivity test was performed using PDO from the patient tissue and the primary cancer characteristics of PDOs were confirmed by pathological comparision with tissue slides. Results The conventional index of drug sensitivity is the AUC of the DRC. In this study, the CODRP index for drug sensitivity test was proposed through multi-parameter analyses considering cancer cell proliferation rate, the cancer diagnosis stage, and AUC values. We tested PDOs from eight patients with lung cancer to verify the CODRP index. According to the anaplastic lymphoma kinase (ALK) rearrangement status, the conventional AUC index for the three ALK-targeted drugs (crizotinib, alectinib, and brigatinib) did not classify into sensitive and resistant groups. The proposed CODRP index-based drug sensitivity test classified ALK-targeted drug responses according to ALK rearrangement status and was verified to be consistent with the clinical drug treatment response. Conclusions Therefore, the PDO-based HTS and CODRP index drug sensitivity tests described in this paper may be useful for predicting and analyzing promising anticancer drug efficacy for patients with lung cancer and can be applied to a precision medicine platform.

Abstract Background Patients with locally advanced, unresectable, non‐small cell lung cancer (NSCLC) receiving definitive concurrent chemoradiation therapy (CCRT) benefit from durvalumab consolidation therapy. However, predictive factors for early relapse during durvalumab maintenance have not yet been identified. Methods The present study included the lung cancer cohort of the Catholic Medical Centers at the Catholic University of Korea from January 2018 to December 2021. A total of 51 NSCLC patients treated with durvalumab consolidation therapy after definitive CCRT were included in the analysis. Early relapse was defined as patients experiencing relapse within 6 months of starting initial durvalumab therapy. Results Among the 51 patients, 15 (29.4%) relapsed during the study period. Median time from initial therapy of durvalumab to progression was 451.00 ± 220.87 days (95% confidence interval [CI]: 18.10–883.90) in overall patients. In multivariate analysis, younger age (adjusted odds ratio [aOR], 0.792; 95% CI: 0.642–0.977; p = 0.030), higher pack‐years (aOR, 1.315; 95% CI: 1.058–1.635; p = 0.014), non‐COPD (aOR, 0.004; 95% CI: 0.000–0.828; p = 0.004) and anemia (aOR, 234.30; 95% CI: 1.212–45280.24; p = 0.042), were independent predictive factors for early relapse during durvalumab consolidation therapy. Conclusion Younger age, higher number of pack‐years, non‐COPD, and anemia were independent predictive factors for early relapse during durvalumab consolidation therapy in patients with unresectable stage III NSCLC after definitive CCRT. Careful patient selection and clinical attention are needed for high‐risk individuals.

Background Surgical resection is the standard treatment for early-stage lung cancer. Since postoperative lung function is related to mortality, predicted postoperative lung function is used to determine the treatment modality. The aim of this study was to evaluate the predictive performance of linear regression and machine learning models. Methods We extracted data from the Clinical Data Warehouse and developed three sets: set I, the linear regression model; set II, machine learning models omitting the missing data: and set III, machine learning models imputing the missing data. Six machine learning models, the least absolute shrinkage and selection operator (LASSO), Ridge regression, ElasticNet, Random Forest, eXtreme gradient boosting (XGBoost), and the light gradient boosting machine (LightGBM) were implemented. The forced expiratory volume in 1 second measured 6 months after surgery was defined as the outcome. Five-fold cross-validation was performed for hyperparameter tuning of the machine learning models. The dataset was split into training and test datasets at a 70:30 ratio. Implementation was done after dataset splitting in set III. Predictive performance was evaluated by R2 and mean squared error (MSE) in the three sets. Results A total of 1,487 patients were included in sets I and III and 896 patients were included in set II. In set I, the R2 value was 0.27 and in set II, LightGBM was the best model with the highest R2 value of 0.5 and the lowest MSE of 154.95. In set III, LightGBM was the best model with the highest R2 value of 0.56 and the lowest MSE of 174.07. Conclusion The LightGBM model showed the best performance in predicting postoperative lung function.

Abstract The metabolic profile of cancerous cells is shifted to meet the cellular demand required for proliferation and growth. Here we show the features of cancer metabolic profiles using peripheral blood of healthy control subjects (n = 78) and lung adenocarcinoma (LUAD) patients (n = 64). Among 121 detected metabolites, diagnosis of LUAD is based on arginine, lysophosphatidylcholine-acyl (Lyso.PC.a) C16:0, and PC-diacyl (PC.aa) C38:3. Network analysis revealed that network heterogeneity, diameter, and shortest path were decreased in LUAD. On the contrary, these parameters were increased in advanced-stage compared to early-stage LUAD. Clustering coefficient, network density, and average degree were increased in LUAD compared to the healthy control, whereas these topologic parameters were decreased in advanced-stage compared to early-stage LUAD. Public LUAD data verified that the genes encoding enzymes for arginine (NOS, ARG, AZIN) and for Lyso.PC and PC (CHK, PCYT, LPCAT) were related with overall survival. Further studies are required to verify these results with larger samples and other histologic types of lung cancer.

Abstract Background The phase III trial IMpower133 showed that platinum and etoposide plus atezolizumab was associated with improved overall survival (OS) and progression free‐survival (PFS) when compared to the placebo group in treatment‐naïve extensive stage (ES) small cell lung cancer (SCLC). Due to superiority in clinical outcomes, combination immunotherapy plus chemotherapy have become mainstay treatment modalities as first‐line treatment in ES‐SCLC. Nevertheless, real‐world data are still lacking and the search for potential biomarkers is essential. This study aimed to evaluate potential predictive biomarkers applicable in ES‐SCLC under combination therapy. Methods Patients with ES‐SCLC under etoposide‐platinum‐atezolizumab enrolled from seven university hospitals affiliated to the Catholic University of Korea were evaluated. Pretreatment clinical parameters were evaluated for association with OS and PFS. Adverse events (AEs) during induction and maintenance phases were also evaluated. p‐values below 0.05 were considered statistically significant. Results A total of 41 patients were evaluated. Six‐month survival was 68.6%. As best response to treatment, 26 (63.4%) showed partial response, nine (22.0%) showed stable disease, and four (9.8%) showed progressive disease. During the induction phase, grade I–II AEs occurred in 22 (53.7%) patients, and grade III–IV AEs occurred in 26 (63.4%) patients. During the maintenance phase, nine out of 25 (36.0%) patients experienced any grade AEs. In multivariate analysis for OS, lactate dehydrogenase (LDH), c‐reactive protein (CRP), and forced vital capacity (%) were significant factors. In multivariate analysis for PFS, sex, and LDH were significant. Conclusion In ES‐SCLC under etoposide‐platinum‐atezolizumab, pretreatment CRP, LDH and FVC (%) were independent predictive factors.

Abstract Background Local treatment (LT) such as radiotherapy and metastasectomy on metastatic sites may improve outcomes in oligometastatic NSCLC patients, but more data are necessary to support LT in oligometastatic diseases. Patients with single extrathoracic metastatic lesion are more likely to benefit from local therapy. In this study, we evaluated the impact of LT in NSCLC patients with a single extrathoracic metastatic lesion. Methods Data were obtained from the Korean Association for Lung Cancer Registry (KALC‐R), a database created using a retrospective sampling survey by the Korean Central Cancer Registry (KCCR) and the Lung Cancer Registration Committee. Results A total of 787 NSCLC patients with a single extrathoracic metastatic lesion were evaluated. In the multivariate analysis for OS, age, female sex, poor performance score, squamous histological subtype, LT, and initial treatment modality showed significant associations. Regarding LT, groups that underwent curative LT were significantly associated with better OS compared to groups that did not undergo LT (p = 0.011, HR 0.448, 95% CI: 0.242–0.829). In the multivariate analysis of patients who underwent LT, poor performance score, initial treatment modality, and T stage were independently associated with poor OS. Compared to the T1 stage, T3 stage showed an HR of 2.470 (95% CI: 1.309–4.663; p = 0.005) and T4 stage showed an HR of 2.063 (95% CI: 1.093–3.904; p = 0.026). Conclusion In NSCLC with a single extrathoracic metastatic lesion, LT, especially for curative purposes, has an independent association with OS. Moreover, among the patients who received LT, factors such as T stage, poor performance score, and initial treatment modality were significantly associated with OS.

Abstract Background The aim of this study was to investigate the characteristics and clinical outcomes of patients with nonsmoking small cell lung cancer (SCLC) using a nationwide registry in Korea. Methods The Korean Association for Lung Cancer developed a registry in cooperation with the Korean Central Cancer Registry (KCCR) and surveyed approximately 10% of recorded lung cancer cases. Results From 2014 to 2016, the KCCR registered 1,043 patients newly diagnosed with SCLC among a total of 8,110 lung cancer patients. In subgroup analysis, Kaplan meier survival analysis showed that the overall survival (OS) was significantly shorter in the nonsmoking subgroup than the ever-smoking subgroup of SCLC patients with extensive disease (6.99 vs. 9.68 months; P = 0.016). Among SCLC patients with limited disease, OS was also shorter in the nonsmoking subgroup, without statistical significance (19.4 vs. 23.5 months; P = 0.247). In a multivariate analysis using a Cox regression model, never smoking was not associated with shorter OS, but older age, extensive stage, poor performance status (Eastern Cooperative Oncology Group grade ≥ 2), male sex, no prophylactic cranial irradiation, and no active treatment (chemotherapy and/or radiotherapy) were associated with poor prognosis. Conclusion This evaluation of an unbiased nationwide survey dataset revealed that a significant proportion of Korean SCLC patients were never-smokers. No history of smoking appeared to be a significant prognostic factor according to the univariate analysis but was confirmed to be statistically insignificant through a multivariate analysis of the total population. Reasons for a poor prognosis may include the possibility that a high rate of the elderly population is composed of nonsmokers who did not receive active treatment.

A variety of anticancer drugs and targeted agents for lung cancer have been developed, but some patients do not respond to these medications as intended. Therefore, there is an urgent need to develop a tool for predicting the anticancer drug response of each patient. Patient-derived tumor organoids (PDOs) have emerged as reliable In vitro tools for developing precision medicine. Herein, we describe a case of a 50-year-old nonsmoking man who was diagnosed with non-small cell lung cancer. Initially, no clinical symptoms were found in this patient. Postoperative pathology confirmed a stage Ib tumor, and an epidermal growth factor receptor (EGFR) mutation (exon21p.L858R) was detected in the patient’s lung tumor specimen. The patient later showed intracranial relapse 17 months after complete resection. An organoid culture was established from the resected brain metastatic tissue and a drug sensitivity test showed, within 72 hours, that the organoids were resistant to gefitinib and osimertinib. Our results recapitulated the patient’s response to anticancer drugs, demonstrating the potential of PDOs for precision medicine.

Abstract Objectives The optimal sequence for the administration of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for treating non‐small cell lung cancer (NSCLC) is still unclear. This study aimed to evaluate the efficacy of sequential afatinib and osimertinib treatment in patients with NSCLC harboring EGFR mutations. Materials and methods Electronic records of patients with EGFR‐mutated NSCLC, who were administered afatinib and osimertinib (group A) or other chemotherapy (group B) between October 2014 and 2019, across 16 hospitals in South Korea were reviewed. The primary outcome, time on treatment (TOT), secondary outcome, and overall survival (OS) were estimated using the Kaplan–Meier method and log‐rank test. Multivariate analyses were performed using the Cox proportional hazards model. Results Of the 737 patients who received frontline afatinib treatment, 324 with complete records were selected (group A: 126, group B: 198). All patients in group A were T790M positive after afatinib, while patients in group B were all negative or unknown. The median TOT was 35.4 months (95% confidence interval [CI]: 27.7−45.6) in group A and 20.8 months (95% CI: 19.4−24.0) in group B. The median TOT with afatinib was 13.0 months (95% CI: 12.0−13.9) overall and 15.7 months (95% CI: 13.9−17.3) in group A. The 2‐ and 3‐year survival rates were 86.0 and 69.3% in group A and 75.9 and 55.3% in group B, respectively. Conclusion Sequential afatinib and osimertinib treatment resulted in better survival rates than treatment with afatinib followed by other chemotherapies.

Abstract Background In this study, we investigated the risk factors of acquired T790M mutation among patients with lung adenocarcinoma with epidermal growth factor receptor (EGFR) tyrosine mutation who were treated with EGFR‐tyrosine kinase inhibitors (TKIs). The aim was to identify the clinical impact of rebiopsy. Methods This multicenter, retrospective cohort study was conducted in South Korea from January 2007 to June 2017. Patients with adenocarcinoma with EGFR mutation who underwent rebiopsy and were treated with EGFR‐TKIs were included. Results Of a total of 352 patients, T790M mutation was identified in 156 (41.9%) at the time of rebiopsy. The median duration from initial biopsy to rebiopsy was 17 months. Univariate logistic regression analysis revealed associations of exon 19 deletion (odds ratio [OR], 1.643; p = 0.026), absence of L858R (OR, 0.627; p = 0.042), and previous EGFR‐TKI treatment duration (OR, 1.039; p

Abstract Background Lung cancer is a frequent comorbidity of chronic obstructive pulmonary disease (COPD). However, the local risk of developing lung cancer related to regional emphysema distribution and clinical outcome has not been investigated. Our aim was to evaluate the impact of regional emphysema score (RES) on tumor location and prognosis in non-small cell lung cancer (NSCLC) patients. Methods We enrolled 457 patients who underwent curative surgery for NSCLC at seven hospitals at The Catholic University of Korea from 2014 to 2018. Emphysema was visually assessed for each lobe, with the lingula as a separate lobe. Semi-quantitative emphysema scoring was classified as follows: 0 = none, 0.5 = 1 to 10%, 1 = 11 to 25%, 2 = 26 to 50%, 3 = 51 to 75%, and 4 = 76 to 100%. An RES was given to each of the six lung zone: the upper, middle, and lower lobes in the right and left lungs. Results There were 145 patients in the high RES (≥ 3) group and 312 in the low RES (

Abstract Background Screening for early detection of lung cancer has been performed in high-risk individuals with smoking history. However, researches on the distribution, clinical characteristics, and prognosis of these high-risk individuals in an actual cohort are lacking. Thus, the objective of this study was to retrospectively review characteristics and prognosis of patients with smoking history in an actual lung cancer cohort. Methods The present study used the lung cancer cohort of the Catholic Medical Centers at the Catholic University of Korea from 2014 to 2017. Patients with non-small cell lung cancer were enrolled. They were categorized into high and low-risk groups based on their smoking history using the national lung screening trial guideline. Distribution, clinical characteristics, and survival data of each group were estimated. Results Of 439 patients, 223 (50.8%) patients were in the high-risk group. Patients in the high-risk group had unfavorable clinical characteristics and tumor biologic features. Overall survival of the high-risk group was significantly shorter than that of the low-risk group with both early (I, II) and advanced stages (III, IV). In multivariate analysis, heavy smoking remained one of the most important poor clinical prognostic factors in patients with lung cancer. It showed a dose-dependent relationship with patients’ survival. Conclusions High-risk individuals had poor clinical outcomes. Patients’ prognosis seemed to be deteriorated as smoking amount increased. Therefore, active screening and clinical attention are needed for high-risk individuals.

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.

Abstract Background Various host factors can promote pneumonia susceptibility of lung cancer patients. However, data about risk factors for pneumonia in lung cancer patients receiving active treatments such as chemotherapy, radiotherapy, and surgical intervention are limited. Thus, the purpose of this study was to identify risk factors for pneumonia development in lung cancer patients. Methods The present study used a lung cancer cohort of the Catholic Medical Center at the Catholic University of Korea from January 2015 to December 2018. Pneumonia was defined by the presence of a new or progressive infiltration on chest imaging together with any of the following: new onset purulent sputum, change in character of chronic sputum, and fever. We ruled out noninfectious infiltration such as drug or radiation toxicity and hydrostatic pulmonary edema. We especially excluded those if computed tomography revealed sharp demarcation consolidation or ground glass opacity limited radiation field. Results A total of 413 patients were enrolled in this study. Pneumonia occurred in 118 (28.6%) patients. The pneumonia group had significantly worse overall survival (OS) than the non-pneumonia group (456.7 ± 35.0 days vs. 813.4 ± 36.1 days, log rank p

Background Although there have been several studies on concordance of different assays testing programmed cell death ligand‐1 (PD‐L1) expression using surgical specimens, studies using real‐world biopsy specimens are scarce. However, many of the non‐small cell lung cancer (NSCLC) cases requiring immunotherapy and thus PD‐L1 testing are unresectable having to rely on small biopsy results. Therefore, we sought to assess the concordance of two diagnostic assays (22C3 and SP263) in evaluating PD‐L1 expression using specimens from CT‐guided transthoracic needle biopsy (TNB) specimens in a routine clinical setting. Methods A total of 202 NSCLC cases that underwent CT‐guided TNB from April 2017 to February 2018 were retrospectively reviewed. Biopsy specimens tested with both 22C3 and SP263 assays were included. Concordance of PD‐L1 expression levels determined by two assays was assessed using intraclass correlation coefficient, and the agreement of dichotomized values at various cutoffs (1%, 25%, and 50%) were assessed using Cohen's κ coefficient of agreement. Results A total of 80 patients (M:F = 47:33, mean age: 68.0 years) were included in the study. Concordance of PD‐L1 expression levels was high (intraclass coefficient: 0.892) between 22C3 and SP263 assays. Agreements at cutoff levels of 1%, 25%, and 50% were also good, with κ values of 0.878, 0.698, and 0.790, respectively. Positive percent agreement was 93.2%, 100.0%, and 95.2% for agreements at 1%, 25%, and 50%. Conclusion There is a high concordance of PD‐L1 expression evaluated with 22C3 and SP263 assays using CT‐guided TNB specimens.

Background Lung cancer is a leading cause of morbidity and mortality worldwide, and the incidence continues to rise. Although many prognostic factors have been identified, the clinical characteristics and outcomes in Korean lung cancer patients are not well defined. Methods Of the 23,254 new lung cancer cases registered at the Korea Central Cancer Registry in 2013, total 489 patients from 19 hospitals were abstracted by the Korean Central Cancer Registry. The clinical data retrospectively analyzed, patients were followed up until December 2015. Results The median age was 69 years (interquartile range, 60–74 years); 65.4% were male and 62.1% were ever-smokers. Cough was the most common initial symptom (33.5%); 13.1% of patients were asymptomatic. While squamous cell carcinoma was the most common subtype in male patients (37.2%), adenocarcinoma was the most frequent histological type in all patients (48.7%) and females (76.3%). The majority of patients received treatment (76.5%), which included surgery, radiation therapy, and chemotherapy. Older age (hazard ratio [HR], 1.037), lower body mass index (HR, 0.904), ever-smoker (HR, 2.003), small cell lung cancer (HR, 1.627), and distant metastasis (HR, 3.990) were independent predictors of mortality. Patients without symptoms (HR, 0.387) and without treatment (HR, 0.364) were associated with a favorable outcome in multivariate Cox analysis. Conclusion Lung cancer in Korea occurs predominantly in elderly patients, with adenocarcinoma being the most frequent subtype. The prognosis was poorer in ever-smokers and older, malnourished, and untreated patients with advanced lung cancer.

Abstract Background A hypoxic microenvironment leads to an increase in the invasiveness and the metastatic potential of cancer cells within tumors via the epithelial-mesenchymal transition (EMT) and cancer stemness acquisition. However, hypoxia-induced changes in the expression and function of candidate stem cell markers and their possible molecular mechanism is still not understood. Methods Lung cell lines were analyzed in normoxic or hypoxic conditions. For screening among the stem cell markers, a transcriptome analysis using next-generation sequencing was performed. For validation, the EMT and stem cell characteristics were analyzed. To determine whether an epigenetic mechanism was involved, the cell lines were treated with a DNA methyltransferase inhibitor (AZA), and methylation-specific PCR and bisulfite sequencing were performed. Results Next-generation sequencing revealed that the CXCR4 expression was significantly higher after the hypoxic condition, which functionally resulted in the EMT and cancer stemness acquisition. The acquisition of the EMT and stemness properties was inhibited by treatment with CXCR4 siRNA. The CXCR4 was activated by either the hypoxic condition or treatment with AZA. The methylation-specific PCR and bisulfite sequencing displayed a decreased CXCR4 promoter methylation in the hypoxic condition. Conclusions These results suggest that hypoxia-induced acquisition of cancer stem cell characteristics was associated with CXCR4 activation by its aberrant promoter demethylation.

Lung cancer, which remains a major cause of mortality worldwide, is a histologically diverse condition and demonstrates substantial phenotypic and genomic diversity among individual patients, manifesting as both intertumoral and intratumoral heterogeneity. This heterogeneity has made it difficult to develop lung cancer models. Two-dimensional (2D) cancer cell lines have been used to study genetic and molecular alterations in lung cancer. However, cancer cell lines have several disadvantages, including random genetic drift caused by long-term culture, a lack of annotated clinical data, and most importantly, the fact that only a subset of tumors shows 2D growth on plastic. Three-dimensional models of cancer have the potential to improve cancer research and drug development because they are more representative of cancer biology and its diverse pathophysiology. Herein, we present an integrated review of current information on preclinical lung cancer models and their limitations, including cancer cell line models, patient-derived xenografts, and lung cancer organoids, and discuss their possible therapeutic applications for drug discovery and screening to guide precision medicine in lung cancer research. Altogether, the success rate of generating lung cancer organoids must be improved, and a lung cancer organoid culture system is necessary to achieve the goal of designing an individualized therapeutic strategy for each lung cancer patient.

The aim of this study was to validate the use of human brain organoids (hBOs) to investigate the therapeutic potential and mechanism of human-neural-crest-derived nasal turbinate stem cells (hNTSCs) in models of Alzheimer’s disease (AD). We generated hBOs from human induced pluripotent stem cells, investigated their characteristics according to neuronal markers and electrophysiological features, and then evaluated the protective effect of hNTSCs against amyloid-β peptide (Aβ1–42) neurotoxic activity in vitro in hBOs and in vivo in a mouse model of AD. Treatment of hBOs with Aβ1–42 induced neuronal cell death concomitant with decreased expression of neuronal markers, which was suppressed by hNTSCs cocultured under Aβ1–42 exposure. Cytokine array showed a significantly decreased level of osteopontin (OPN) in hBOs with hNTSC coculture compared with hBOs only in the presence of Aβ1–42. Silencing OPN via siRNA suppressed Aβ-induced neuronal cell death in cell culture. Notably, compared with PBS, hNTSC transplantation significantly enhanced performance on the Morris water maze, with reduced levels of OPN after transplantation in a mouse model of AD. These findings reveal that hBO models are useful to evaluate the therapeutic effect and mechanism of stem cells for application in treating AD.

Background Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure to evaluate suspicious lymph node involvement of lung cancer because computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography-CT (PET-CT) have limitations in their sensitivity and specificity. There are a number of benign causes of false positive lymph node such as anthracosis or anthracofibrosis, pneumoconiosis, old or active tuberculosis, interstitial lung disease, and other infectious conditions including pneumonia. The purpose of this study was to evaluate possible causes of false positive lymph node detected in chest CT or PET-CT. Methods Two hundred forty-seven patients who were initially diagnosed with lung cancer between May 2009 and December 2012, and underwent EBUS-TBNA to confirm suspicious lymph node involvement by chest CT or PET-CT were analyzed for the study. Results Of 247 cases, EBUS-TBNA confirmed malignancy in at least one lymph node in 189. The remaining 58 patients whose EBUS-TBNA results were negative were analyzed. Age ≥65, squamous cell carcinoma as the histologic type, and pneumoconiosis were related with false-positive lymph node involvement on imaging studies such as chest CT and PET-CT. Conclusion These findings suggest that lung cancer staging should be done more carefully when a patient has clinically benign lymph node characteristics including older age, squamous cell carcinoma, and benign lung conditions.

In 2021, approximately 248,530 new prostate cancer (PCa) cases are estimated in the United States. Hispanic/Latinos (H/L) are the second largest racial/ethnic group in the US. The objective of this study was to assess DNA methylation patterns between aggressive and indolent PCa along with ancestry proportions in 49 H/L men from Puerto Rico (PR). Prostate tumors were classified as aggressive (n = 17) and indolent (n = 32) based on the Gleason score. Genomic DNA samples were extracted by macro-dissection. DNA methylation patterns were assessed using the Illumina EPIC DNA methylation platform. We used ADMIXTURE to estimate global ancestry proportions. We identified 892 differentially methylated genes in prostate tumor tissues as compared with normal tissues. Based on an epigenetic clock model, we observed that the total number of stem cell divisions (TNSC) and stem cell division rate (SCDR) were significantly higher in tumor than adjacent normal tissues. Regarding PCa aggressiveness, 141 differentially methylated genes were identified. Ancestry proportions of PR men were estimated as African, European, and Indigenous American; these were 24.1%, 64.2%, and 11.7%, respectively. The identification of DNA methylation profiles associated with risk and aggressiveness of PCa in PR H/L men will shed light on potential mechanisms contributing to PCa disparities in PR population.

INTRODUCTION:Tobacco use disorder (TUD), previously known as nicotine dependence, was associated with increased risk of lung cancer. However, little is known about the prevalence of TUD and symptom manifestation in smokers with lung cancer. OBJECTIVES:The aim of the present study was to investigate the prevalence of TUD using DSM-5 diagnostic criteria in patients diagnosed with lung cancer and analyze their tobacco use characteristics. METHODS:A total of 200 histologically confirmed lung cancer patients who used tobacco within the prior 12-month period at the time of diagnosis were recruited for this study. Participants were assessed using interviewer-administered questionnaires to determine TUD symptoms and smoking-related behaviors, and self-administered Fagerstrom Test for Nicotine Dependence (FTND) was also administered. RESULTS:The prevalence of DSM-5 TUD was 92.0% (n = 184). Of a total of 200 subjects, 23 (11.5%), 35 (17.5%), and 126 (63.0%) were classified into mild, moderate, and severe TUD categories, respectively. A total of 19 (81.3%) moderate TUD and 98 (77.8%) severe TUD patients had attempted smoking cessation. Of these subjects, 21 (21.4%) severe TUD and 12 (63.2%) moderate TUD patients tried more than three times. The number of satisfied criteria under DSM-5 TUD was positively correlated with FTND score, cumulative lifetime smoking amount, and daily smoking levels. CONCLUSIONS:Smokers diagnosed with lung cancer showed a high prevalence of DSM-5 TUD. Their heavy and consistent tobacco use suggests reduced motivation to abstain from smoking.

Lung cancer specialists play an important role in designing and implementing lung cancer screening. We aimed to describe their 1) attitudes toward low-dose lung computed tomography (LDCT) screening, 2) current practices and experiences of LDCT screening and 3) attitudes and opinions towards national lung cancer screening program (NLCSP). We conducted a national web-based survey of pulmonologists, thoracic surgeons, medical oncologists, and radiological oncologists who are members of Korean Association for Lung Cancer (N = 183). Almost all respondents agreed that LDCT screening increases early detection (100%), improves survival (95.1%), and gives a good smoking cessation counseling opportunity (88.6%). Most were concerned about its high false positive results (79.8%) and the subsequent negative effects. Less than half were concerned about radiation hazard (37.2%). Overall, most (89.1%) believed that the benefits outweigh the risks and harms. Most (79.2%) stated that they proactively recommend LDCT screening to those who are eligible for the current guidelines, but the screening propensity varied considerably. The majority (77.6%) agreed with the idea of NLCSP and its beneficial effect, but had concerns about the quality control of CT devices (74.9%), quality assurance of radiologic interpretation (63.3%), poor access to LDCT (56.3%), and difficulties in selecting eligible population using self-report history (66.7%). Most (79.2%) thought that program need to be funded by a specialized fund rather than by the National Health Insurance. The opinions on the level of copayment for screening varied. Our findings would be an important source for health policy decision when considering for NLCSP in Korea.

INTRODUCTION:A combination of platelet and lymphocyte to monocyte ratio (LMR) (abbreviated as COP-LMR) has been recently evaluated as systemic inflammatory marker for prognostication in lung cancer. While previous study on COP-LMR has evaluated its prognostic value in NSCLC patients who underwent curative resections, the combination of these two markers has not been evaluated in advanced NSCLC yet. OBJECTIVES:In this study, we evaluated the prognostic value of COP-LMR in stage IV NSCLC with malignant pleural effusion under active anticancer treatment. METHODS:Between January 2012 and July 2016, 217 patients with stage IV NSCLC and MPE undergoing active anticancer treatment were selected for evaluation. If patients had both low LMR (< 2.47) and increased platelet (> 30.0 ×10(4) mm-3), they were assigned to COP-LMR group 2. Patients with one parameter were assigned to COP-LMR group 1. If none, patients were assigned to COP-LMR group 0. RESULTS:Median overall survival (OS) (P < 0.001), progression free survival (PFS) (P < 0.001) and histological feature (P = 0.003) showed significant differences among COP-LMR groups. For COP-LMR groups 0, 1 and 2, median survival times were 35.9, 14.7 and 7.4 months, respectively, while median progression free times were 19.2, 13.3 and 7.4 months, respectively. Older age, male, low albumin, high CRP and high COP-LMR (0 vs 1, P = 0.021, hazard ratio (HR): 1.822, 95% confidence interval (CI): 1.096-3.027 and 0 vs 2, P = 0.003, HR: 2.464, 95% CI: 1.373-4.421) were independent predictive factors for shorter OS. Age, sex, histology, albumin, or CRP had no significant influence on PFS. High COP-LMR was the significant factor in predicting shorter PFS (0 vs 1, P = 0.116 and 0 vs 2, P = 0.007, HR: 1.902, 95% CI: 1.194-3.028). CONCLUSIONS:A combination of pretreatment LMR and platelet levels can be used to predict short survival in stage IV NSCLC patients who underwent active anticancer treatment.

OBJECTIVES:Despite a sharp increase in e-cigarette use, there is debate about whether e-cigarettes are a viable alternative for harm reduction, and the forms that regulation should take. Healthcare providers can be effective in offering guidance to patients and their families and shaping regulatory policy. We described lung cancer specialists' attitudes toward e-cigarettes and its regulation. METHODS:We undertook a nationwide survey of pulmonologists, thoracic surgeons, medical and radiological oncologists who are members of Korean Association for Lung Cancer. Survey items included beliefs and attitudes toward e-cigarettes, attitudes toward e-cigarette regulation and preparedness on discussing e-cigarettes with their patients. RESULTS:Most respondents believed that e-cigarettes are not safer than conventional tobacco cigarettes (75.7%) or smokeless tobacco (83.2%), and feared that discussing e-cigarettes with the patients would encourage use (65.4%). They did not consider it a smoking cessation treatment (78.3%), and thus would not recommend it to smokers who do not want to quit (82.2%) or who failed to quit with conventional smoking cessation treatment (74.1%). Most respondents supported all examples of e-cigarette regulations, including the safety and quality check (97.8%), warning label (97.8%), advertisement ban (95.1%), restriction of flavoring (78.4%), minimum purchasing age (99.5%), and restriction of indoor use (94.6%). Most learned about e-cigarettes from media and advertisements, or conversation with patients rather than through professional scientific resources, and reported discomfort when discussing e-cigarette with patients. CONCLUSION:Lung cancer specialist physicians in Korea doubt the safety of e-cigarette and use of e-cigarette as smoking cessation treatment, and supported strict regulation. However, only 20% reported that they obtained information on e-cigarettes from the scientific literature and many lacked adequate knowledge based on scientific evidence, suggesting the need for better preparedness. Nevertheless, the views of professionals revealed from our study could help to develop clinical guidelines and regulatory guidance.

Lung cancer and chronic obstructive pulmonary disease (COPD) are two major lung diseases. Epidermal growth factor receptor (EGFR) mutations, v-Ki-ras2 Kirsten rat sarcoma (KRAS) mutations and anaplastic lymphoma kinase (ALK) gene rearrangements represent driver mutations that are frequently assessed on initial evaluation of non-small-cell lung cancer (NSCLC). The present study focused on the expression of driver mutations in NSCLC patients presenting with COPD and further evaluated the association between NSCLC and COPD. Data from 501 consecutive patients with histologically proven recurrent or metastatic NSCLC were analyzed retrospectively. The patients underwent spirometry and genotyping of EGFR, ALK, and KRAS in tissue samples. Patient characteristics and expression of driver mutations were compared between the COPD and non-COPD groups. Among 350 patients with spirometric results, 106 (30.3%) were diagnosed with COPD, 108 (30.9%) had EGFR mutations, 31 (8.9%) had KRAS mutations, and 34 (9.7%) showed ALK rearrangements. COPD was independently associated with lower prevalences of EGFR mutations (95% confidence interval [CI], 0.254-0.931, p = 0.029) and ALK rearrangements (95% CI, 0.065-0.600, p = 0.004). The proportions of EGFR mutations and ALK rearrangements decreased as the severity of airflow obstruction increased (p = 0.001). In never smokers, the prevalence of EGFR mutations was significantly lower in the COPD group than in the non-COPD group (12.7% vs. 49.0%, p = 0.002). COPD-related NSCLC patients exhibited low prevalences of EGFR mutations and ALK rearrangements compared with the non-COPD group. Further studies are required regarding the molecular mechanisms underlying lung cancer associated with COPD.

Purpose This study aimed to report the final analysis of time-on-treatment (TOT) and overall survival (OS) in patients with advancedstage epidermal growth factor receptor (EGFR)+ non--small cell lung cancer (NSCLC) who received sequential afatinib and osimertinib and to compare the outcomes with other second-line regimens (comparator group). Materials and Methods In this updated report, the existing medical records were reviewed and rechecked. TOT and OS were updated and analyzed according to clinical features using the Kaplan-Meier method and log-rank test. TOT and OS were compared with those of the comparator group, in which most patients received pemetrexed-based treatments. A multivariable Cox proportional hazard model was used to evaluate features that could affect survival outcomes. Results The median observation time was 31.0 months. The follow-up period was extended to 20 months. A total of 401 patients who received first-line afatinib were analyzed (166 with T790M+ and second-line osimertinib, and 235 with unproven T790M and other second-line agents). Median TOTs on afatinib and osimertinib were 15.0 months (95% confidence interval [CI], 14.0 to 16.1) and 11.9 months (95% CI, 8.9 to 14.6), respectively. The median OS in the osimertinib group was 54.3 months (95% CI, 46.7 to 61.9), much longer than that in the comparator group. In patients who received osimertinib, the OS was longest with Del19+ (median, 59.1; 95% CI, 48.7 to 69.5). Conclusion This is one of the largest real-world studies reporting the encouraging activity of sequential afatinib and osimertinib in Asian patients with EGFR+ NSCLC who acquired the T790M mutation, particularly Del19+. [ABSTRACT FROM AUTHOR]

Background/Aim: Programmed death ligand-1 (PD-L1) expression is known to be a predictive biomarker for response to immunotherapy in non-small cell lung cancer (NSCLC). However, PD-L1 is not always a reliable predictive biomarker. In the present study, we aimed to compare responses to immunotherapy according to smoking status in NSCLC patients receiving immunotherapy in second line or further line treatment. Patients and Methods: The lung cancer registry database of the Catholic Medical Center, Seoul, Republic of Korea was used. Patients were eligible for this study if they were diagnosed with histologically confirmed NSCLC and received immune checkpoint inhibitors (ICIs) as second-line or further line therapy from January 2017 to December 2021. Results: Overall, 220 patients with NSCLC treated with ICIs were enrolled. There were 40 never smokers, 73 former smokers, and 107 current smokers. In multivariate analysis, smoking status, pathologic type, and PD-L1 expression were significant factors affecting PFS. Sex, ECOG performance status, pathologic type, and PD-L1 expression were significant factors affecting OS. Conclusion: Smoking status at diagnosis of lung cancer could be a predictive biomarker for response to ICIs in patients with advanced NSCLC. [ABSTRACT FROM AUTHOR]

Purpose Although osimertinib is the standard-of-care treatment of epidermal growth factor receptor (EGFR) T790M mutation–positive non–small cell lung cancer, real-world evidence on the efficacy of osimertinib is not enough to reflect the complexity of the entire course of treatment. Herein, we report on the use of osimertinib in patients with EGFR T790M mutation–positive non–small cell lung cancer who had previously received EGFR tyrosine kinase inhibitor (TKI) treatment in Korea. Materials and Methods Patients with confirmed EGFR T790M after disease progression of prior EGFR-TKI were enrolled and administered osimertinib 80 mg daily. The primary effectiveness outcome was progression-free survival, with time-to-treatment discontinuation, treatment and adverse effects leading to treatment discontinuation, and overall survival being the secondary endpoints. Results A total of 558 individuals were enrolled, and 55.2% had investigator-assessed responses. The median progression-free survival was 14.2 months (95% confidence interval [CI], 13.0 to 16.4), and the median time-to-treatment discontinuation was 15.0 months (95% CI, 14.1 to 15.9). The median overall survival was 36.7 months (95% CI, 30.9 to not reached). The benefit with osimertinib was consistent regardless of the age, sex, smoking history, and primary EGFR mutation subtype. However, hepatic metastases at the time of diagnosis, the presence of plasma EGFR T790M, and the shorter duration of prior EGFR-TKI treatment were poor predictors of osimertinib treatment. Ten patients (1.8%), including three with pneumonitis, had to discontinue osimertinib due to severe adverse effects. Conclusion Osimertinib demonstrated its clinical effectiveness and survival benefit for EGFR T790M mutation–positive in Korean patients with no new safety signals. [ABSTRACT FROM AUTHOR]

Objective: The quantitative reverse transcription polymerase chain reaction (qPCR) is the most accurate and reliable technique for analysis of gene expression. Endogenous reference genes (RGs) have been used to normalize qPCR data, although their expression may vary in different tissues and experimental conditions. Verification of the stability of RGs in selected samples is a prerequisite for reliable results. Therefore, we attempted to identify the most stable RGs in the hypothalamic-pituitary-gonadal (HPG) axis in sows. Methods: The cycle threshold values of nine commonly used RGs (18S, HPRT1, GAPDH, RPL4, PPIA, B2M, YWHAZ, ACTB, and SDHA) from HPG axis-related tissues in the domestic sows in the different stages of estrus cycle were analyzed using two RG-finding programs, geNorm and Normfinder, to rank the stability of the pool of RGs. In addition, the effect of the most and least stable RGs was examined by normalization of the target gene, gonadotropin-releasing hormone (GnRH), in the hypothalamus. Results: PPIA, HPRT1, and YWHAZ were the most stable RGs in the HPG axis-related tissues in sows regardless of the stages of estrus cycle. In contrast, traditional RGs, including 18S and ACTB, were found to be the least stable under these experimental conditions. In particular, in the normalization of GnRH expression in the hypothalamus against several stable RGs, PPIA, HPRT1, and YWHAZ, could generate significant (p<0.05) elevation of GnRH in the preovulatory phase compared to the luteal phase, but the traditional RGs with the least stability (18S and ACTB) did not show a significant difference between groups. Conclusion: These results indicate the importance of verifying RG stability prior to commencing research and may contribute to experimental design in the field of animal reproductive physiology as reference data. [ABSTRACT FROM AUTHOR]