Comparison of Homologous Recombination Repair Gene Next-Generation Sequencing Analysis in Patients With Metastatic Castration-Resistant Prostate Cancer Between Local and Central Laboratories in Korea.

Background: Following success of the phase III PROfound trial, the poly (ADP-ribose) polymerase (PARP) inhibitor olaparib was approved by the US Food and Drug Administration in May 2020 for adult patients with deleterious homologous recombination repair (HRR) gene-mutated metastatic castration-resistant prostate cancer (mCRPC). As locally adopted multigene panel next-generation sequencing (NGS) assays for selecting PARP inhibitor candidates have not been thoroughly evaluated, we compared the analytical performance of the FoundationOne CDx (Foundation Medicine, Inc., Cambridge, MA, USA) (central laboratory) and other NGS assays (local laboratory) with samples from the PROfound trial in Korea. Methods: One hundred PROfound samples (60 HRR mutation [HRRm] cases and 40 non-HRRm cases) were analyzed. The results of HRR gene mutation analysis were compared between the FoundationOne CDx and two other NGS assays [SureSelect Custom Design assay (Agilent Technologies, Inc., Santa Clara, CA, USA) and Oncomine Comprehensive assay (Thermo Fisher Scientific, Inc., Waltham, MA, USA)]. Results: The positive percent agreement for single nucleotide variants (SNVs) and insertion/deletions (indels) between the central laboratory and local laboratory was 98.7%-100.0%. The negative percent agreement and overall percent agreement (OPA) for SNVs and indels between central and local laboratories were both 100%. Compared with that of the FoundationOne CDx assay, the OPA for copy number variations of the Oncomine Comprehensive and SureSelect Custom assays reached 99.8%-100%. Most mCRPC patients harboring a deleterious genetic variant were successfully identified with both local laboratory assays. Conclusions: The NGS approach at a local laboratory showed comparable analytical performance for identifying HRRm status to the FoundationOne CDx assay used at the central laboratory.

Prediction of urine culture results by automated urinalysis with digital flow morphology analysis.

To investigate the association between the results of urinalysis and those of concurrent urine cultures, and to construct a prediction model for the results of urine culture. A total of 42,713 patients were included in this study. Patients were divided into two independent groups including training and test datasets. A novel prediction algorithm, designated the UTOPIA value, was constructed with the training dataset, based on an association between the results of urinalysis and those of concurrent urine culture. The diagnostic performance of the UTOPIA value was validated with the test dataset. Six variables were selected for the equation of the UTOPIA value: age of higher UTI risk [odds ratio (OR), 2.069125], female (OR, 1.400648), nitrite (per 1 grade; OR, 3.765457), leukocyte esterase (per 1 grade; OR, 1.701586), the number of WBCs (per 1 × 106/L; OR, 1.000121), and the number of bacteria (per 1 × 106/L; OR, 1.004195). The UTOPIA value exhibited an area under the curve value of 0.837 when validated with the independent test dataset. The UTOPIA value displayed good diagnostic performance for predicting urine culture results, which would help to reduce unnecessary culture. Different cutoffs can be used according to the clinical indication.

An optimized BRCA1/2 next-generation sequencing for different clinical sample types.

OBJECTIVE: A simultaneous detection of germline and somatic mutations in ovarian cancer (OC) using tumor materials is considered to be cost-effective for BRCA1/2 testing. However, there are limited studies of the analytical performances according to various sample types. The aim of this study is to propose a strategy for routine BRCA1/2 next-generation sequencing (NGS) screening based on analytical performance according to different sample types. METHODS: We compared BRCA1/2 NGS screening assay using buffy coat, fresh-frozen (FF) and formalin-fixed paraffin-embedded (FFPE) from 130 samples. RESULTS: The rate of repeated tests in a total of buffy coat, FF and FFPE was 0%, 8%, and 34%, respectively. The accuracy of BRCA1/2 NGS testing was 100.0%, 99.9% and 99.9% in buffy coat, FFPE and FF, respectively. However, due to the presence of variant allele frequency (VAF) shifted heterozygous variants, tumor materials (FFPE and FF) showed lower sensitivity (95.5%-99.0%) than buffy coat (100%). Furthermore, FFPE showed 51.4% of the positive predictive value (PPV) on account of sequence artifacts. When performed in the post-filtration process, PPV was increased by approximately 20% in FFPE. Buffy coat showed 100% of sensitivity, specificity and accuracy in BRCA1/2 NGS test. CONCLUSIONS: On the comparison of the analytical performance according to different sample types, the buffy coat was not affected by sequencing artifacts and VAF shifted variants. Therefore, the blood test should be given priority in detecting germline BRCA1/2 mutation, and tumor materials could be suitable to detect somatic mutations in OC patients without identifying germline BRCA1/2 mutation.

Profiling cancer-associated genetic alterations and molecular classification of cancer in Korean gastric cancer patients.

Recently, the Cancer Genome Atlas (TCGA) Research Network and Asian Cancer Research Group provided a new classification of gastric cancer (GC) to aid the development of biomarkers for targeted therapy and predict prognosis. We studied associations between genetically aberrant profiles of cancer-related genes, environmental factors, and histopathological features in 107 paired gastric tumor-non-tumor tissue GC samples. 6.5% of our GC cases were classified as the EBV subtype, 17.8% as the MSI subtype, 43.0% as the CIN subtype, and 32.7% as the GS subtype. The distribution of four GC subgroups based on the TCGA and our dataset were similar. The MSI subtype showed a hyper-mutated status and the best prognosis among molecular subtype. However, molecular classification based on the four GC subtypes showed no significant survival differences in terms of overall survival (p= 0.548) or relapse-free survival (RFS, p=0.518). The P619fs*43 in ZBTB20 was limited to MSI group (n= 5/19, 26.3%), showing similar trends observed in TCGA dataset. Genetic alterations of the RTK/RAS/MAPK and PI3K/AKT/mTOR pathways were detected in 34.6% of GC cases (37 individual cases). We also found two cases with likely pathogenic variants (NM_004360.4: c. 2494 G>A, p.V832M) in the CDH1 gene. Here, we classified molecular subtypes of GC according to the TCGA system and provide a critical starting point for the design of more appropriate clinical trials based on a comprehensive analysis of genetic alterations in Korean GC patients.