Genomic and transcriptomic profiles associated with response to eribulin and nivolumab combination in HER-2-negative metastatic breast cancer.

BACKGROUND: Biomarkers for predicting response to the immunotherapy and chemotherapy combination in breast cancer patients are not established. In this study, we report exploratory genomic and transcriptomic analyses of pretreatment tumor tissues from patients enrolled in phase II clinical trial of a combination of eribulin and nivolumab for HER-2-negative metastatic breast cancer (MBC) (KORNELIA trial, NCT04061863). METHODS: We analyzed associations between tumor molecular profiles based on genomic (n = 76) and transcriptomic data (n = 58) and therapeutic efficacy. Patients who achieved progression-free survival (PFS) ≥ 6 months were defined as PFS6-responders and PFS6-nonresponders otherwise. FINDINGS: Analyses on tumor mutation burden (TMB) showed a tendency toward a favorable effect on efficacy, while several analyses related to homologous recombination deficiency (HRD) indicated a potentially negative impact on efficacy. Patients harboring TP53 mutations showed significantly poor PFS6 rate and PFS, which correlated with the enrichment of cell cycle-related signatures in PFS6-nonresponders. High antigen presentation gene set enrichment scores (≥ median) were significantly associated with longer PFS. Naïve B-cell and plasma cell proportions were considerably higher in long responders (≥ 18 months). INTERPRETATION: Genomic features including TMB, HRD, and TP53 mutations and transcriptomic features related to immune cell profiles and cell cycle may distinguish responders. Our findings provide insights for further exploring the combination regimen and its biomarkers in these tumors.

Renal Cell Carcinoma Metastasis to the Penis: A Case Report and Literature Review.

Metastasis to the penis from renal cell carcinoma (RCC) or any other primary cancer site is unusual; when it does occur, it often involves multiple organs. A 75-year-old man presented with penile pain and swelling. Three months earlier, he had open radical nephrectomy with thrombectomy and was diagnosed with clear-cell RCC with tumor thrombosis in the inferior vena cava. The follow-up imaging indicated metastasis to the penis, prompting a total penectomy due to worsening pain. The excised mass displayed features consistent with metastatic RCC. This case underscores the need to consider rare metastatic sites, such as the metastasis of RCC to the penis, in RCC patients.

Renal cell carcinoma metastasis to the penis: A case report and literature review.

Metastasis to the penis from RCC or any other primary cancer site is unusual; when it does occur, it often involves multiple organs. A 75-year-old man presented with penile pain and swelling. Three months earlier, he had open radical nephrectomy with thrombectomy and was diagnosed with clear-cell RCC with tumor thrombosis in the IVC. The follow-up imaging indicated metastasis in the penis, prompting a total penectomy due to worsening pain. The excised mass displayed features consistent with metastatic RCC. This case underscores the need to consider rare metastatic sites, such as metastasis of RCC to the penis, in RCC patients.

Comparative RNA-Seq Analysis Revealed Tissue-Specific Splicing Variations during the Generation of the PDX Model.

Tissue-specific gene expression generates fundamental differences in the function of each tissue and affects the characteristics of the tumors that are created as a result. However, it is unclear how much the tissue specificity is conserved during grafting of the primary tumor into an immune-compromised mouse model. Here, we performed a comparative RNA-seq analysis of four different primary-patient derived xenograft (PDX) tumors. The analysis revealed a conserved RNA biotype distribution of primary-PDX pairs, as revealed by previous works. Interestingly, we detected significant changes in the splicing pattern of PDX, which was mainly comprised of skipped exons. This was confirmed by splicing variant-specific RT-PCR analysis. On the other hand, the correlation analysis for the tissue-specific genes indicated overall strong positive correlations between the primary and PDX tumor pairs, with the exception of gastric cancer cases, which showed an inverse correlation. These data propose a tissue-specific change in splicing events during PDX formation as a variable factor that affects primary-PDX integrity.

Genomic hypomethylation in cell-free DNA predicts responses to checkpoint blockade in lung and breast cancer.

Genomic hypomethylation has recently been identified as a determinant of therapeutic responses to immune checkpoint blockade (ICB). However, it remains unclear whether this approach can be applied to cell-free DNA (cfDNA) and whether it can address the issue of low tumor purity encountered in tissue-based methylation profiling. In this study, we developed an assay named iMethyl, designed to estimate the genomic hypomethylation status from cfDNA. This was achieved through deep targeted sequencing of young LINE-1 elements with > 400,000 reads per sample. iMethyl was applied to a total of 653 ICB samples encompassing lung cancer (cfDNA n = 167; tissue n = 137; cfDNA early during treatment n = 40), breast cancer (cfDNA n = 91; tissue n = 50; PBMC n = 50; cfDNA at progression n = 44), and ovarian cancer (tissue n = 74). iMethyl-liquid predicted ICB responses accurately regardless of the tumor purity of tissue samples. iMethyl-liquid was also able to monitor therapeutic responses early during treatment (3 or 6 weeks after initiation of ICB) and detect progressive hypomethylation accompanying tumor progression. iMethyl-tissue had better predictive power than tumor mutation burden and PD-L1 expression. In conclusion, our iMethyl-liquid method allows for reliable noninvasive prediction, early evaluation, and monitoring of clinical responses to ICB therapy.

Study on Rolling Defects of Al-Mg Alloys with High Mg Content in Normal Rolling and Cross-Rolling Processes.

This study investigated defect formation and strain distribution in high-Mg-content Al-Mg alloys during normal rolling and cross-rolling processes. The finite element analysis (FEA) revealed the presence of wave defects and strain localization-induced zipper cracks in normal cold rolling, which were confirmed by the experimental results. The concentration of shear strain played a significant role in crack formation and propagation. However, the influence of wave defects was minimal in the cross-rolling process, which exhibited a relatively uniform strain distribution. Nonetheless, strain concentration at the edge and center regions led to the formation of zipper cracks and edge cracks, with more pronounced propagation observed in the experiments compared to FEA predictions. Furthermore, texture evolution was found to be a crucial factor affecting crack propagation, particularly with the development of the Goss texture component, which was observed via electron backscattered diffraction analysis at bending points. The Goss texture hindered crack propagation, while the Brass texture allowed cracks to pass through. This phenomenon was consistent with both FEA and experimental observations. To mitigate edge crack formation and propagation, potential strategies involve promoting the formation of the Goss texture at the edge through alloy and process conditions, as well as implementing intermediate annealing to alleviate stress accumulation. These measures can enhance the overall quality and reliability of Al-Mg alloys during cross-rolling processes. In summary, understanding the mechanisms of defect formation and strain distribution in Al-Mg alloys during rolling processes is crucial for optimizing their mechanical properties. The findings of this study provide insights into the challenges associated with wave defects, strain localization, and crack propagation. Future research and optimization efforts should focus on implementing strategies to minimize defects and improve the overall quality of Al-Mg alloys in industrial applications.

Bilateral epididymal tuberculosis causing abscess formation and male infertility: a case report and literature review.

Background: Epididymal tuberculosis (TB) is an uncommon form of TB, although it is known to develop frequently in the male reproductive system. Infertility is rare but important among subsequent possible complications caused by the disease, particularly in young males. Moreover, it is difficult to differentiate epididymal TB from other epididymo-testicular diseases. Herein, we report a rare case of a young patient recently diagnosed with bilateral epididymal TB causing male infertility. Case Description: We report the case of a 37-year-old patient who presented with left testicular pain and swelling lasting for about 8 months. He had no comorbidities, including pulmonary TB. Additionally, he had no children and was worried about infertility. Physical examination revealed a firm and tender mass, which was palpable in the left epididymal area, measuring 3.5 cm × 2.2 cm in diameter. Acid-fast bacilli staining and polymerase chain reaction of the urine were negative. Semen analysis showed no sperm in the semen, implying azoospermia diagnosis. Scrotal ultrasonography was suggestive of severe left epididymitis with abscess formation without abnormal appearance of the testicle. Due to persistent testicular pain, intermittent fever, and severe epididymitis with abscess formation, the patient underwent epididymectomy. Surgical exploration of the testicle revealed a severely swollen and firm epididymis with abscess materials and hard and dilated vas deferens connected to the epididymis, implying severe inflammatory reactions. The histopathological examination revealed chronic granulomatous inflammation with caseous necrosis in the epididymis tissue. According to histopathological results, the patient was treated with anti-TB pharmacological treatment. About 1 month after the surgery, he presented with pain in the right testicular area, implying bilateral TB epididymis. After completion of the pharmacological treatment, the patient had no complaints, such as pain or swelling in both testicular areas. Conclusions: Physicians should consider the possibility of epididymal TB in patients with persistent testicular symptoms for early diagnosis. When a definitive diagnosis of epididymal TB is established, or clinically suspected, immediate treatment initiation, including pharmacological and, if needed, surgical treatment, should be performed to prevent subsequent complications, including abscess formation or male infertility, particularly in young males.

Determination of microbiological characteristics and risk factors associated with bacteriuria and symptomatic urinary tract infection in patients with retained ureteral stents: an observational study.

Background: The maintenance of ureteral stents is vital in patients with severe ureteral stricture or ureteral obstruction. This study aimed to identify microbiological characteristics and factors associated with bacteriuria and symptomatic urinary tract infection (UTI) in these patients. Methods: This study is an observational cross-sectional study. From August 2018 to January 2021, urine samples from 307 consecutive patients who required stent indwelling and had replaced ureteral stents more than once were collected before the replacement procedure and analyzed by microbiological testing. Patient demographics, laboratory test results, and data on dependent functional capacity and indwelling urethral catheter use were collected from all patients. Additionally, ureteral stenting duration and number of previous ureteral stent replacements were reviewed. The primary endpoint was the incidence rate of bacteriuria and extended-spectrum beta-lactamase (ESBL)-producing bacteria. The secondary endpoint was the factors predisposing patients with ureteral stents to bacteriuria, ESBL-producing bacteria, and the development of symptomatic UTIs. Results: Bacteriuria was observed in 187 patients (60.9%). Among the bacteria identified in urine, Escherichia coli was the most commonly isolated microorganism, followed by Enterococcus, Candida species, Staphylococcus species, Klebsiella, and Pseudomonas. Using multivariate analysis, bacteriuria was significantly associated with old age, female sex, presence of diabetes mellitus, impaired renal function, and longer duration of ureteral stenting. ESBL-producing bacteria were detected in 52 isolates (27.8%). The incidence of ESBL-producing bacteria in urine culture was associated with old age and longer ureteral stenting duration. Additionally, symptomatic UTIs developed in 22 patients (7.2%). Dependent functional capacity, impaired renal function, and longer ureteral stenting duration were significantly associated with symptomatic UTIs. Conclusions: Infections related to ureteral stents showed a specific microorganism profile and resistance pattern compared to community-acquired UTIs. Additionally, we identified the factors associated with bacteriuria and symptomatic UTI in patients with retained ureteral stents and deduced that these may be associated with better outcomes in patients with retained ureteral stents.

MHC II immunogenicity shapes the neoepitope landscape in human tumors.

Despite advances in predicting physical peptide-major histocompatibility complex I (pMHC I) binding, it remains challenging to identify functionally immunogenic neoepitopes, especially for MHC II. By using the results of >36,000 immunogenicity assay, we developed a method to identify pMHC whose structural alignment facilitates T cell reaction. Our method predicted neoepitopes for MHC II and MHC I that were responsive to checkpoint blockade when applied to >1,200 samples of various tumor types. To investigate selection by spontaneous immunity at the single epitope level, we analyzed the frequency spectrum of >25 million mutations in >9,000 treatment-naive tumors with >100 immune phenotypes. MHC II immunogenicity specifically lowered variant frequencies in tumors under high immune pressure, particularly with high TCR clonality and MHC II expression. A similar trend was shown for MHC I neoepitopes, but only in particular tissue types. In summary, we report immune selection imposed by MHC II-restricted natural or therapeutic T cell reactivity.

Ureteral fibroepithelial polyp protruding into the bladder which mimics a bladder tumour: a case report and literature review.

Background: Ureteral fibroepithelial polyp is a rare benign lesion of the urinary tract. The incidence of the disease has been increasing recently; however, the aetiology of this tumour remains unclear. Early diagnosis and management are important, and endoscopic treatment is increasingly being preferred worldwide. Case Description: We report the case of a 49-year-old patient who presented with urinary frequency, intermittent haematuria, and an echogenic bladder mass found on pelvic sonography. Cystoscopy revealed an irregularly shaped large bladder mass, suggesting a benign or malignant bladder tumour. On subsequent examination, intravenous urography (IVU) and computed tomography showed a large lobulated contour filling defect in the bladder, measuring approximately 4 cm, with a suspected finding of a long stalk in the left distal ureter. Ureteroscopy revealed a long and narrow pedunculated tumour in the left distal ureter protruding into the bladder cavity through the ureteral orifice. On endoscopic excision, the attached stalk of the polyp into the ureter was cut using holmium:yttrium aluminium garnet (YAG) laser. The polyp was completely excised and extracted in its entirety, including the section protruding into the bladder. Histopathological findings confirmed the diagnosis of a fibroepithelial polyp. There was no sign of complication or recurrence on computed tomography performed after 12 months. Conclusions: The ureteral fibroepithelial polyp protruding into the bladder mimicked a bladder tumour and was successfully treated by endoscopic resection, with no complications or recurrence. Endoscopic treatment is an effective and safe method to treat fibroepithelial polyps of the ureter.

Complete genome sequences of Lactococcus lactis JNU 534, a potential food and feed preservative.

A new bacteriocin-producing lactic acid bacteria isolated from kimchi was identified as Lactococcus lactis JNU 534, presenting preservative properties for foods of animal origin. In this study, we present the complete genome sequence of the bacterial strain JNU 534. The final complete genome assembly consists of one circular chromosome (2,443,687 bp [base pair]) with an overall GC (guanine-cytosine) content of 35.2%, one circular plasmid sequence (46,387 bp) with a GC content of 34.5%, and one circular contig sequence (7,666 bp) with a GC content of 36.2%.

Usefulness of the prostate health index in predicting the presence and aggressiveness of prostate cancer among Korean men: a prospective observational study.

BACKGROUND: We aimed to evaluate the usefulness of the Beckman Coulter prostate health index (PHI) and to compare it with total prostate-specific antigen (PSA) levels and related derivatives in predicting the presence and aggressiveness of prostate cancer (PCa) in the Korean population. METHODS: A total of 140 men who underwent their first prostate biopsy for suspected PCa were included in this prospective observational study. The diagnostic performance of total PSA, free PSA, %free PSA, [-2] proPSA (p2PSA), %p2PSA, and PHI in detecting and predicting the aggressiveness of PCa was estimated using the receiver operating characteristic curve (ROC) and logistic multivariate regression analyses. RESULTS: Of 140 patients, PCa was detected in 63 (45%) of participants, and 48 (76.2%) of them had significant cancer with a Gleason score (GS) ≥ 7. In the whole group, the area under the curve (AUC) for ROC analysis of tPSA, free PSA, %fPSA, p2PSA, %p2PSA, and PHI were 0.63, 0.57, 0.69, 0.69, 0.72, and 0.76, respectively, and the AUC was significantly greater in the PHI group than in the tPSA group (p = 0.005). For PCa with GS ≥ 7, the AUCs for tPSA, free PSA, %fPSA, p2PSA, %p2PSA, and PHI were 0.62, 0.58, 0.41, 0.79, 0.86, and 0.87, respectively, and the AUC was significantly greater in the PHI group than in the tPSA group (p < 0.001). In the subgroup with tPSA 4-10 ng/mL, both %p2PSA and PHI were strong independent predictors for PCa (p = 0.007, p = 0.006) and significantly improved the predictive accuracy of a base multivariable model, including age, tPSA, fPSA and %fPSA, using multivariate logistic regression analysis. (p = 0.054, p = 0.048). Additionally, at a cutoff PHI value > 33.4, 22.9% (32/140) of biopsies could be avoided without missing any cases of aggressive cancer. CONCLUSIONS: This study shows that %p2PSA and PHI are superior to total PSA and %fPSA in predicting the presence and aggressiveness (GS ≥ 7) of PCa among Korean men. Using PHI, a significant proportion of unnecessary biopsies can be avoided.

The role of preoperative ureteral stenting in retrograde intrarenal surgery in renal stone patients: a propensity score-matched study.

BACKGROUND: The purpose of this study was to investigate the effect of preoperative ureteral stenting on retrograde intrarenal surgery (RIRS). METHODS: We retrospectively analyzed RIRS cases from October 2014 to June 2017. Patients were divided into two groups according to preoperative ureteral stent insertion. The characteristics of the patients [age, body mass index (BMI), sex, previous disease history, hemoglobin, creatinine, estimated glomerular filtration rate (eGFR)], characters of stone (size, number, density, location), ureteral access sheath (UAS) success rate, perioperative complication, operative time, hospitalization time, period with stent, postoperative urinary tract infection (UTI) rate, stone free rate (SFR), and additional treatment rate were analyzed. RESULTS: RIRS was performed for 122 patients. Seventy-three patients had preoperative ureteral stents before RIRS, while 49 patients did not have preoperative ureteral stents. The median size of the stone was 14.5 mm. Overall SFR was 87.7%. Preoperative eGFR was relatively high in patients who underwent preoperative stenting (68.18 vs. 79.01 mL/min/1.73 m2, P=0.042). Preoperative stenting led to improvement in the success rate of UAS insertion (97.3% vs. 87.8%, P=0.038) during surgery. Before and after propensity score matching revealed a significant difference in operation time when the diameter of the stone was smaller than 1 cm (P=0.019 and P=0.004). However, there was no significant difference in operation time, postoperative UTI rate, additional treatment rate, or SFR. CONCLUSIONS: Preoperative ureteral stenting can facilitate UAS insertion, and reduce operation time in RIRS for stones with a diameter less than 1 cm.

Day Temperature Difference and Aggravation of Low Urinary Tract Symptom in Benign Prostate Hypertrophy Patients in Korea: A National Health Insurance Service-National Cohort-based Study.

OBJECTIVE: To investigate the symptom deterioration of patients with benign prostatic hyperplasia (BPH) according to the difference in daily temperature. PATIENTS AND METHODS: From the National Health Insurance Service database, we collected and analyzed data on patients with BPH in 6 major metropolitan areas in Korea between January 2008 and December 2017. We investigated the rate of emergency room visits as well as the rate of urethral catheter insertion. RESULTS: In total, 1,446,465 patients were enrolled in this study. When the daily temperature difference was below 4°C, 28.5 patients visited the emergency room daily, while 42.2 patients visited the emergency room daily when the daily temperature difference exceeded 14°C. When the daily temperature difference was more than 14°C, about 48.0% more patients visited the emergency room than when the daily temperature difference was below 4°C. After visiting the emergency room, there were 11.9 patients who had a catheter inserted daily at the daily temperature difference below 4°C. When the daily temperature difference was more than 14°C, the number of catheter insertion cases was 17.8 patients daily, which was 49.2% higher than that of below 4°C. By time, surgery was performed most frequently within 3 months after visiting the emergency room. CONCLUSION: Day temperature difference appear to be related to the Lower urinary tract symptom of BPH patients.

Prospective clinical evaluation of Momguard non-invasive prenatal test in 1011 Korean high-risk pregnant women.

Clinical performance of the Momguard non-invasive prenatal test (NIPT) was evaluated in a cohort of Korean pregnant women. The foetal trisomies 21, 18 and 13 (T21, T18 and T13) were screened by low-coverage massive parallel sequencing in the maternal blood. Among the 1011 confirmed samples, 32 cases (3.2%) had positive NIPT results. Of these positive cases, 20 cases of T21, all cases of T18 and two cases of T13 had concordant karyotype findings. Only one case out of the remaining 979 negative NIPT samples showed a false negative result. The overall sensitivity and specificity of Momguard to detect the three chromosomal aneuploidies were 96.8% and 99.8%, respectively. Momguard is a clinically useful tool for the detection of T21, T18 and T13 in singleton pregnancy. However, as other NIPT tests, it carries the risk of false positive and false negative results. Hence, the genetic counsellors should provide these limitations to the examinees.Impact StatementWhat is already known on this subject? The NIPT approach using massive parallel sequencing (MPS) showed high sensitivity and specificity in various clinical studies. These results are based on analysis systems using their own bioinformatics algorithms.What the results of this study add? When this NIPT technology was introduced in Korea, the first biological specimens collected in Korea were transported overseas for processing in overseas laboratories and analysed by other country's analysis methods. We needed our own NIPT algorithm and developed Momguard NIPT for the first time in Korea. This study attempted to evaluate this Momguard NIPT protocol prospectively in a large number of samples obtained from three Korean hospitals.What the implications are of these findings for clinical practice and/or further research? The overall sensitivity and specificity to identify T13, T18 and T21 were 96.8% and 99.8%, respectively. These accuracy values were comparable to that of other studies. From this study, we found that Momguard is a clinically useful tool for the detection of three chromosomal aneuploidies. However, as other NIPT tests, it carries the risk of false positive and false negative results. Hence, the genetic counsellors should provide these limitations to the examinees.

Frequency of hereditary neuropathy with liability to pressure palsies (HNPP) due to 17p11.2 deletion in a Korean newborn population.

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disorder mainly due to a deletion of chromosome 17p11.2 including PMP22 (PMP22 Del HNPP). The prevalence of HNPP is estimated to be 0.84 to 16 per 100,000, but could be underestimated because of the mild symptoms of HNPP. In this study, we estimated the prevalence of PMP22 Del HNPP in a Korean newborn population who underwent next-generation sequencing (NGS)-based copy number variation (CNV) analysis. Of the 11,885 newborns tested by NGS-based CNV analysis, 17p11.2 deletions were found in seven samples. The prevalence of PMP22 Del HNPP was estimated to be 58.9 per 100,000 (95% confidence interval (CI), 25.8-116.5) or 1 in 1698 (95% CI, 1/909-1/5000). Our data suggest that PMP22 Del HNPP might not be uncommon at least in the Korean population.

Universally applicable, quantitative PCR method utilizing fluorescent nucleobase analogs.

We herein describe a novel quantitative PCR (qPCR) method, which operates in both signal-off and on manners, by utilizing a unique property of fluorescent nucleobase analogs. The first, signal-off method is developed by designing the primers to contain pyrrolo-dC (PdC), one of the most common fluorescent nucleobase analogs. The specially designed single-stranded primer is extended to form double-stranded DNA during PCR and the fluorescence signal from the PdCs incorporated in the primer is accordingly reduced due to its conformation-dependent fluorescence properties. In addition, the second, signal-on method is devised by designing the primers to contain 5'-overhang sequences complementary to the PdC-incorporated DNA probes. At the initial phase, the PdC-incorporated DNA probes are hybridized to the 5'-overhang sequences of the primer, exhibiting the significantly quenched fluorescence signal, but are detached by either hydrolysis or strand displacement reaction during PCR, leading to the highly enhanced fluorescence signal. This method is more advanced than the first one since it produces signal-on fluorescence response and permits the use of a single PdC-incorporated DNA probe for the detection of multiple target nucleic acids, remarkably decreasing the assay cost. With these novel qPCR methods, we successfully quantified target nucleic acids derived from sexually transmitted disease (STD) pathogens with high accuracy. Importantly, the proposed strategies overcome the major drawbacks in the current SYBR Green and TaqMan probe-based qPCR methods such as low specificity and high assay cost.

Impact of metabolic status on the association of serum vitamin D with hypogonadism and lower urinary tract symptoms/benign prostatic hyperplasia.

OBJECTIVE: The objective of this study is to investigate the impact of metabolic status on associations of serum vitamin D with hypogonadism and lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: A total of 612 men underwent physical examination, biochemical/hormonal blood testing, and transrectal prostate ultrasound. Moreover, the subjects filled out standard questionnaires for identification and grading of LUTS and hypogonadism symptoms. Parameters were statistically compared with independent t-tests and correlation analyses. RESULTS: Vitamin D levels positively correlated with total testosterone (TT) but not with prostate volume or International Prostate Symptom Score (IPSS). Patients with metabolic syndrome had significantly lower vitamin D levels, which were not correlated with TT, prostate volume, or IPSS. However, vitamin D was positively correlated with TT, and negatively correlated with prostate volume and quality-of-life IPSS in subjects without metabolic syndrome. CONCLUSION: The clinical usefulness of vitamin D for treatment of hypogonadism or LUTS/BPH varies according to metabolic status.

Frequency of pathogenic germline mutation in CHEK2, PALB2, MRE11, and RAD50 in patients at high risk for hereditary breast cancer.

PURPOSE: This study was performed to evaluate the frequency of mutations in CHEK2, PALB2, MRE11, and RAD50 among Korean patients at high risk for hereditary breast cancer. METHODS: A total of 235 Korean patients with hereditary breast cancer who tested negative for BRCA1/2 mutation were enrolled to this study. Entire coding regions of CHEK2, PALB2, MRE11, and RAD50 were analyzed using massively parallel sequencing (MPS). Sequence variants detected by MPS were confirmed by Sanger sequencing. RESULTS: Six patients (2.5 %) were found to have pathogenic variants in CHEK2 (n = 1), PALB2 (n = 2), MRE11 (n = 1), and RAD50 (n = 2). Among the pathogenic variants, PALB2 c.2257C>T was previously reported in other studies, while CHEK2 c.1245dupC, PALB2 c.1048C>T, MRE11 c.1773_1774delAA, RAD50 c.1276C>T, and RAD50 c.3811_3813delGAA were newly identified in this study. A total of 15 missense variants were found in the four genes among 26 patients; 7 patients had a variant in CHEK2, 11 in PALB2, 2 in MRE11, and 6 in RAD50. When in silico analyses were performed to the 15 missense variants, six variants (CHEK2 c.686A>G, PALB2 c.1492G>T, PALB2 c.3054G>C, MRE11 c.140C>T, RAD50 c.1456C>T, and RAD50 c.3790C>T) were predicted to be deleterious. CONCLUSIONS: Pathogenic variants in CHEK2, PALB2, MRE11, and RAD50 were detected in a small proportion of Korean patients with features of hereditary breast cancer.