Personalized therapy guided by longitudinal liquid biopsies for treatment of leptomeningeal disease from lung adenocarcinoma: A case report.

Molecular-based targeted therapies have significantly benefited certain patients with cancer; however, those with leptomeningeal disease (LMD) persistently exhibit a poor prognosis and are often excluded from clinical trials. Tumor-derived cell-free (cf)DNA, found in the cerebrospinal fluid (CSF) of patients with LMD, can assist in diagnosis and tracking of disease progression. However, the utilization of CSF to direct targeted cancer therapy has yet to be extensively explored. The present study reported the case of a patient with lung adenocarcinoma and LMD who was monitored by performing a series of liquid biopsies of CSF and blood. Targeted sequencing was performed on cfDNA from the CSF and plasma, and the variant allele frequencies (VAFs) of BRAF and NRAS mutations were assessed and analyzed in conjunction with the clinical presentation of the patient. The patient then underwent serial chemotherapy, radiation therapy, immunotherapy and targeted treatment based on the results of the liquid biopsies. Upon the LMD diagnosis, a BRAF p.V600E mutation was detected in plasma cfDNA. Consequently, the patient was treated with vemurafenib and responded favorably to this consolidation treatment for 13 months. After a relapse in July 2018, both BRAF p.V600E and NRAS p.Q61K mutations were detected in CSF supernatant and sediment cell samples, suggesting drug resistance. Therefore, the treatment strategy for the patient changed to cobimetnib plus vemurafenib. Notably, the changes of VAF in the CSF supernatant samples were associated with the clinical status of the patient. The patient survived for 33 months post-LMD diagnosis. The present case report highlights the potential use of liquid biopsy in personalized therapy, as it was instrumental in informing the combinational treatment plan of the patient, which ultimately proved beneficial.

The genomic characteristics of RET fusion positive tumors in Chinese non-small cell lung cancer (NSCLC) patients.

BACKGROUND: Approximately 1-2% of non-small cell lung cancer (NSCLC) patients harbor RET (rearranged during transfection) fusions. The oncogenic RET fusions could lead to constitutive kinase activation and oncogenesis. METHODS: 1746 Chinese NSCLC patients were analyzed in this study. Tumor tissues were collected, and were formalin fixed, paraffin-embedded (FFPE) and archived. Peripheral blood (PB) samples were also collected from each patient as control. In addition, we selected 17 of them for cfDNA NGS testing and 14 tumor samples for immunohistochemistry testing using PD-L1 rabbit monoclonal antibody, clones 28-8 (Abcam, Cambridge, UK). RESULTS: Of the 1746 NSCLC cases, RET rearrangements were identified in 25 cases (1.43%) with locally advanced or metastatic NSCLC, of which 20 (80%) were female. We found that 14 out of 25 patients had an KIF5B-RET fusion, with KIF5B exon15-RET exon12, KIF5B exon23-RET exon12, and KIF5B exon24-RET exon11 detected in 14, 3, and 1 patients, respectively. We also identified one novel RET fusion partner PLCE1 and 4 intergenic-breakpoint fusions. CONCLUSION: In this study, using the hybrid capture based next generation sequencing (NGS) techniques, we revealed the genomic profiling for the patients with RET fusion-positive NSCLC. To the best of our knowledge, this is the first study that exhibited the detailed breakpoints of Chinese NSCLC patients with RET rearrangement, and we found a novel new partner PLCE1. The results provided genomic information for patients with RET fusion which is significant for personalized clinical management in the era of precision medicine.

Comprehensive profiling of 1015 patients' exomes reveals genomic-clinical associations in colorectal cancer.

The genetic basis of colorectal cancer (CRC) and its clinical associations remain poorly understood due to limited samples or targeted genes in current studies. Here, we perform ultradeep whole-exome sequencing on 1015 patients with CRC as part of the ChangKang Project. We identify 46 high-confident significantly mutated genes, 8 of which mutate in 14.9% of patients: LYST, DAPK1, CR2, KIF16B, NPIPB15, SYTL2, ZNF91, and KIAA0586. With an unsupervised clustering algorithm, we propose a subtyping strategy that classisfies CRC patients into four genomic subtypes with distinct clinical characteristics, including hypermutated, chromosome instability with high risk, chromosome instability with low risk, and genome stability. Analysis of immunogenicity uncover the association of immunogenicity reduction with genomic subtypes and poor prognosis in CRC. Moreover, we find that mitochondrial DNA copy number is an independent factor for predicting the survival outcome of CRCs. Overall, our results provide CRC-related molecular features for clinical practice and a valuable resource for translational research.

Comprehensive characterization of CRC with germline mutations reveals a distinct somatic mutational landscape and elevated cancer risk in the Chinese population.

OBJECTIVE: Hereditary colorectal cancer (CRC) accounts for approximately 5%-10% of all CRC cases. The full profile of CRC-related germline mutations and the corresponding somatic mutational profile have not been fully determined in the Chinese population. METHODS: We performed the first population study investigating the germline mutation status in more than 1,000 (n = 1,923) Chinese patients with CRC and examined their relationship with the somatic mutational landscape. Germline alterations were examined with a 58-gene next-generation sequencing panel, and somatic alterations were examined with a 605-gene panel. RESULTS: A total of 92 pathogenic (P) mutations were identified in 85 patients, and 81 likely pathogenic (LP) germline mutations were identified in 62 patients, accounting for 7.6% (147/1,923) of all patients. MSH2 and APC was the most mutated gene in the Lynch syndrome and non-Lynch syndrome groups, respectively. Patients with P/LP mutations had a significantly higher ratio of microsatellite instability, highly deficient mismatch repair, family history of CRC, and lower age. The somatic mutational landscape revealed a significantly higher mutational frequency in the P group and a trend toward higher copy number variations in the non-P group. The Lynch syndrome group had a significantly higher mutational frequency and tumor mutational burden than the non-Lynch syndrome group. Clustering analysis revealed that the Notch signaling pathway was uniquely clustered in the Lynch syndrome group, and the MAPK and cAMP signaling pathways were uniquely clustered in the non-Lynch syndrome group. Population risk analysis indicated that the overall odds ratio was 11.13 (95% CI: 8.289-15.44) for the P group and 20.68 (95% CI: 12.89-33.18) for the LP group. CONCLUSIONS: Distinct features were revealed in Chinese patients with CRC with germline mutations. The Notch signaling pathway was uniquely clustered in the Lynch syndrome group, and the MAPK and cAMP signaling pathways were uniquely clustered in the non-Lynch syndrome group. Patients with P/LP germline mutations exhibited higher CRC risk.

Case Report: Cetuximab in Combination With Chemotherapy for the Treatment of Multifocal Hepatic Metastases From Colorectal Cancer Guided by Genetic Tests.

Hepatic metastases were reported in up to 70% of colorectal cancer patients, among which multifocal hepatic metastasis represents one of the complications that lead to poor prognosis. The majority of the patients carrying multifocal hepatic metastases required pharmaceutical treatments to reduce the tumor size prior to surgical resection. However, the clinical responses to pharmaceutical agents were difficult to predict due to the heterogeneous nature of the multifocal tumors. Here, we report a case with multifocal hepatic metastases from colorectal cancer that was resistant to the primary chemotherapy and Bevacizumab plus chemotherapy, but responded to the combined therapy of Cetuximab and FOLFOX. Genetic tests had revealed that the tumor was highly metastatic due to the mutations of the WNT signaling pathway, and the metastatic tumors might be sensitive to Cetuximab. Consistent with the molecular characterizations, the metastatic tumors continue to emerge after chemotherapy, and rapidly relapsed in great numbers after liver resection. However, the combined therapy of Cetuximab and FOLFOX guided by the genetic tests significantly reduced the size and number of metastatic tumors. To conclude, deciphering the mutation profiles of multifocal metastatic tumors may guide the determination of treatment tactics, which may benefit the patients with non-resectable advanced carcinoma.

Prognostic Factors of Colorectal Cancer: A Comparative Study on Patients With or Without Liver Metastasis.

BACKGROUND: Radical or palliative surgery with subsequent adjuvant therapy is the routine treatment for stage II/III colorectal cancer(CRC) and some stage IV CRC patients. This study aimed to clarify the prognostic clinicopathological and genetic factors for these patients. METHODS: Fifty-five stage II-IV CRC patients undergoing surgery and adjuvant therapy were recruited, including patients without liver metastasis(5 at stage II, 21 at stage III) and with liver metastasis(29 at stage IV). Genetic alterations of the primary cancer tissues were investigated by whole exome sequencing(WES). Patients were followed up to 1652 days(median at 788 days). RESULTS: The mutational landscape of primary CRC tissue of patients with or without liver metastasis was largely similar, although the mutational frequency of TRIM77 and TCF7L2 was significantly higher in patients with liver metastasis. Several main driver gene co-mutations, such as TP53-APC, APC-KRAS, APC-FRG1, and exclusive mutations, such as TP53-CREBBP, were found in patients with liver metastasis, but not in patients without liver metastasis. No significant difference was found between the two groups in aberrant pathways. If stage II-IV patients were studied altogether, relapse status, SUPT20HL1 mutations, Amp27_21q22.3 and Del8_10q23.2 were independent risk factors(P<0.05). If patients were divided into two groups by metastatic status, surgery types and Amp6_20q13.33 were independent risk factors for patients without liver metastasis(P<0.05), while TRIM77 mutations were the only independent risk factor for patients with liver metastasis(P<0.05). CONCLUSIONS: Surgery types and Amp6_20q13.33 were independent risk factors for CRC patients without liver metastasis, and TRIM77 mutations were the independent risk factor for CRC patients with liver metastasis.

Metastatic Low-Grade Sarcoma with CARS-ALK Fusion Dramatically Responded to Multiple ALK Tyrosine Kinase Inhibitors: A Case Report with Comprehensive Genomic Analysis.

This article reports a case of advanced metastatic low-grade sarcoma. The patient was diagnosed with an inoperable large (14 × 12 cm) lesion on his neck in September 2015 and underwent two ineffective chemotherapies in the following 4 months. Interestingly, although several pathologists could not agree on the histopathological diagnosis, the precise molecular pathological diagnosis was obtained using next-generation sequencing (NGS) and finally brought excellent therapeutic effects. The patient was detected to have CARS-ALK fusion by NGS and then was successfully treated with crizotinib orally. He received surgical resection of primary and metastatic lesions after tumor shrinkage. The combined treatment brought a durable response for 40 months. Although the tumor recurred in July 2019, the patient has been responding well to the second-line ALK tyrosine kinase inhibitor alectinib to date. We performed whole genome sequencing on the patient's primary, metastatic, and recurrent tumors and did comprehensive genomic analysis. Furthermore, our analysis results revealed that a whole genome duplication event might have happened during tumorigenesis of this case. KEY POINTS: To our best knowledge, this is the first report of a very successful treatment with first- and second-line ALK tyrosine kinase inhibitors for CARS-ALK fusion-positive metastatic low-grade sarcoma. Molecular pathological result can guide precision treatment for sarcoma, even when the exact histopathology cannot be obtained. Multiple samples from this patient were analyzed using whole genome sequencing. Results provided detailed genomic characteristics and showed tumor evolution of this low-grade sarcoma case. A whole genome duplication event might have happened during tumorigenesis of this low-grade sarcoma case.

The contribution of hereditary cancer-related germline mutations to lung cancer susceptibility.

BACKGROUND: Germline variations may contribute to lung cancer susceptibility besides environmental factors. The influence of germline mutations on lung cancer susceptibility and their correlation with somatic mutations has not been systematically investigated. METHODS: In this study, germline mutations from 1,026 non-small cell lung cancer (NSCLC) patients were analyzed with a 58-gene next-generation sequencing (NGS) panel containing known hereditary cancer-related genes, and were categorized based on American College of Medical Genetics and Genomics (ACMG) guidelines in pathogenicity, and the corresponding somatic mutations were analyzed using a 605-gene NGS panel containing known cancer-related genes. RESULTS: Plausible genetic susceptibility was found in 4.7% of lung cancer patients, in which 14 patients with pathogenic mutations (P group) and 34 patients with likely-pathogenic mutations (LP group) were identified. The ratio of the first degree relatives with lung cancer history of the P groups was significantly higher than the Non-P group (P=0.009). The ratio of lung cancer patients with history of other cancers was higher in P (P=0.0007) or LP (P=0.017) group than the Non-P group. Pathogenic mutations fell most commonly in BRCA2, followed by CHEK2 and ATM. Likely-pathogenic mutations fell most commonly in NTRK1 and EXT2, followed by BRIP1 and PALB2. These genes are involved in DNA repair, cell cycle regulation and tumor suppression. By comparing the germline mutation frequency from this study with that from the whole population or East Asian population (gnomAD database), we found that the overall odds ratio (OR) for P or LP group was 17.93 and 15.86, respectively, when compared with the whole population, and was 2.88 and 3.80, respectively, when compared with the East Asian population, suggesting the germline mutations of the P and LP groups were risk factors for lung cancer. Somatic mutation analysis revealed no significant difference in tumor mutation burden (TMB) among the groups, although a trend of lower TMB in the pathogenic group was found. The SNV/INDEL mutation frequency of TP53 in the P group was significantly lower than the other two groups, and the copy number variation (CNV) mutation frequency of PIK3CA and MET was significantly higher than the Non-P group. Pathway enrichment analysis found no significant difference in aberrant pathways among the three groups. CONCLUSIONS: A proportion of 4.7% of patients carrying germline variants may be potentially linked to increased susceptibility to lung cancer. Patients with pathogenic germline mutations exhibited stronger family history and higher lung cancer risk.

The Genomic Characteristics of ALK Fusion Positive Tumors in Chinese NSCLC Patients.

Anaplastic lymphoma kinase (ALK) fusion events account for ~3-7% genetic alterations in patients with non-small cell lung cancer (NSCLC). In this study, we identified the ALK fusion patterns and a novel ALK fusion partner in 44 ALK positive NSCLC patients using a customized HapOncoCDx panel, and identified ALK fusion partners. The most common partner is EML4, forming the variant 1 (v1, E13:A20, 18/44), variant 2 (v2, E20:A20, 5/44), and variant 3 (v3, E6:A20, 13/44). Moreover, we detected a new ALK fusion partner HMBOX1. At the mutation level, TP53 is the most frequently mutated gene (24%), followed by ALK (12%) and STED2 (12%). The median tumor mutation burden (TMB) of these samples is 2.29 mutations/Mb, ranging from 0.76 mut/Mb to 16.79 muts/Mb. We further elaborately portrayed the TP53 mutation sites on the peptide sequence of the encoded protein by lollipop. The mutational signature and copy number alterations (CNAs) of the samples were also analyzed. The CNA events were found in 13 (13/44) patients, and the most commonly amplified genes were MDM2 (n = 4/13) and TERT (n = 4/13). Together, these results may guide personalized clinical management of patients with ALK fusion in the era of precision medicine.

Circulating Tumor DNA Is Capable of Monitoring the Therapeutic Response and Resistance in Advanced Colorectal Cancer Patients Undergoing Combined Target and Chemotherapy.

Colorectal cancer (CRC) is a highly lethal disease worldwide. The majority of patients receiving targeted therapy or chemotherapy develop drug resistance, while its molecular mechanism remains to be elucidated. The plasma circulating tumor DNA (ctDNA) exhibited the potential in identifying gene variations and monitoring drug resistance in CRC treatment. In this study, we monitored the ctDNA mutational changes in advanced CRC patients underwent first-line therapy with bevacizumab and cetuximab combined with chemotherapy. The mutation spectrum of 43 patients was established by a 605-gene next-generation sequencing (NGS) panel. The baseline measurement shows that genes with the highest mutation frequency were TP53 (74%), APC (58%), KRAS (40%), SYNE1 (33%), LRP1B (23%), TOP1 (23%), and PIK3CA (21%). Mutations in TP53, APC, and KRAS were detected in 29 paired plasma and tissue samples with the consistency of 81, 67, and 42%, respectively. Clinically targetable gene mutations, such as APC, RNF43, SMAD4, BRAD1, KRAS, RAF1, and TP53, were also identified in ctDNA. The overall consistency between ctDNA and tissue samples was 54.6%. Alleviation of mutational burden in BRAF, KRAS, AMER1, and other major driving genes was observed following the first-line therapy. Patients with KRAS and TP53 mutations in tissues appeared to benefit more than the wild-type counterpart. The dynamic change of plasma mutation status was consistent with the tissue tumor burden and was closely correlated with disease progression. In conclusion, ctDNA monitoring is a useful method for molecular genotyping of colorectal cancer patients. Dynamic changes in resistance can be sensitively monitored by gene variation status, which potentially helps to develop treatment strategy.

Targeted deep sequencing helps distinguish independent primary tumors from intrapulmonary metastasis for lung cancer diagnosis.

PURPOSE: Multiple lung lesions found in a single patient at the time of diagnosis often pose a diagnostic dilemma: are these lesions independent primary tumors (IPT) or the result of intrapulmonary metastases (IPM)? While traditional pathological methods sometimes have difficulty distinguishing IPM from IPT, modern molecular profiling based on next-generation sequencing techniques may provide a new strategy. METHODS: Sixteen patients with multiple tumors were enrolled in this study. We performed targeted deep sequencing (~ 2000 × coverage) on a total of 40 tumors and matched blood samples. We compared mutational profiles between tumors within each patient and across patients to evaluate if they were genetically related. Computed tomographic images and histological staining were also used to validate tumor relationships. RESULTS: A total of 125 mutations were identified in 16 patients. Twelve out of fourteen patients whose histological diagnoses favored IPT did not have any shared mutations in their multiple tumors. The other two showed discrepancies: Pt01 had a shared EGFR exon19 deletion in the two lung tumors found, and Pt16 had one common mutation (BRAFD594G) in two out of five lung tumors. Pt14 with lung metastasis from salivary gland adenoid cystic carcinoma had shared mutations; and Pt15 with suspected intrapulmonary metastasis (IPM) had identical mutations between the two tumors. Visualized data can be readily accessed through the website: mlc.opengene.org. CONCLUSION: Analysis of overlapping mutations among different tumors assists physicians in distinguishing IPM from IPT. Our findings demonstrate that DNA sequencing can provide additional evidence in clinical practice when pathology is inadequate to make a conclusive diagnosis.

Gencore: an efficient tool to generate consensus reads for error suppressing and duplicate removing of NGS data.

BACKGROUND: Removing duplicates might be considered as a well-resolved problem in next-generation sequencing (NGS) data processing domain. However, as NGS technology gains more recognition in clinical application, researchers start to pay more attention to its sequencing errors, and prefer to remove these errors while performing deduplication operations. Recently, a new technology called unique molecular identifier (UMI) has been developed to better identify sequencing reads derived from different DNA fragments. Most existing duplicate removing tools cannot handle the UMI-integrated data. Some modern tools can work with UMIs, but are usually slow and use too much memory. Furthermore, existing tools rarely report rich statistical results, which are very important for quality control and downstream analysis. These unmet requirements drove us to develop an ultra-fast, simple, little-weighted but powerful tool for duplicate removing and sequence error suppressing, with features of handling UMIs and reporting informative results. RESULTS: This paper presents an efficient tool gencore for duplicate removing and sequence error suppressing of NGS data. This tool clusters the mapped sequencing reads and merges reads in each cluster to generate one single consensus read. While the consensus read is generated, the random errors introduced by library construction and sequencing can be removed. This error-suppressing feature makes gencore very suitable for the application of detecting ultra-low frequency mutations from deep sequencing data. When unique molecular identifier (UMI) technology is applied, gencore can use them to identify the reads derived from same original DNA fragment. Gencore reports statistical results in both HTML and JSON formats. The HTML format report contains many interactive figures plotting statistical coverage and duplication information. The JSON format report contains all the statistical results, and is interpretable for downstream programs. CONCLUSIONS: Comparing to the conventional tools like Picard and SAMtools, gencore greatly reduces the output data's mapping mismatches, which are mostly caused by errors. Comparing to some new tools like UMI-Reducer and UMI-tools, gencore runs much faster, uses less memory, generates better consensus reads and provides simpler interfaces. To our best knowledge, gencore is the only duplicate removing tool that generates both informative HTML and JSON reports. This tool is available at: https://github.com/OpenGene/gencore.

Comprehensive analysis of POLE and POLD1 Gene Variations identifies cancer patients potentially benefit from immunotherapy in Chinese population.

POLE/POLD1 gene variants have been suggested as potential markers for immunotherapy due to their significant association with the tumor mutational burden (TMB), an effective indicator for response prediction in immunotherapy. However, the correlation of POLE/POLD1 variants with MSI, MMR, TMB, MMR-related and key driver gene mutations needs to be defined to support patient recruitment and therapeutic effect assessment in immunotherapy. 1,392 Chinese cancer patients were recruited, and the correlation of POLE/POLD1 variants with existing immunotherapeutic markers and cancer pathways was investigated. A next-generation sequencing panel including 605 cancer-related genes was used for variant sequencing. It was found that the frequency of POLE variants was not statistically different from that in COSMIC database, while the frequency of POLD1 variants was significantly higher in lung cancer. c.857 C > G and c.2091dupC were potential high frequency variants in Chinese cancer patients. Patients carrying POLE damaging variants were significantly younger than POLE/POLD1 WT patients. Patients carrying POLE/POLD1 damaging variants exhibited significantly higher TMB and frequency of MMR gene variants than POLE/POLD1 WT patients. Patients with POLE damaging variants also exhibited significantly higher frequency of driver gene variants than POLE/POLD1 WT patients. Further analysis showed that POLE damaging variants may affect the cancer development through MMR, TGFß and RTK/RAS/RAF signaling pathways, and POLD1 through MMR pathways. In conclusion, this study identified key characteristics and regions of POLE/POLD1 genes that correlates with TMB, MMR gene mutations and key driver gene mutations, and provided theoretical and practical basis for patient selection based on POLE/POLD1 gene status in immunotherapy.

Circulating tumor DNA sequencing for colorectal cancers: A comparative analysis of colon cancer and rectal cancer data.

BACKGROUND: Circulating tumor DNA (ctDNA) has been recognized as a promising biomarker for colorectal cancer (CRC) early diagnosis and postoperative monitoring. However, we hypothesize that the clinical value of ctDNA sequencing may differ for colon cancer (CC) and rectal cancer (RC). METHODS: Forty-three patients with primary CRC were prospectively enrolled. Tumor tissue samples, paired preoperative plasma samples and a series of postoperative plasma samples were obtained. Mutations in each sample were identified and compared. RESULTS: For 73.0% patients, at least one concordant mutation was detected in both tumor tissue DNA and paired preoperative ctDNA. The mutation concordance rate were higher in CC patients compared to RC patients (92.3% vs 45.5%; p= 0.004). For early stage patients, the mutation concordance rate was 72.7%. The recurrence rate was 33.3% for patients with postoperative ctDNA positive mutations, and 3.4% for patients with negative ctDNA (HR 10.767; 95% CI 1.1-103.8; p= 0.040). CONCLUSION: Liquid biopsy via ctDNA sequencing has great potential for the early detection and postoperative monitoring of CRC. The DNA of CC tissues is more likely to be released into blood than the DNA of RC tissues. This should be considered when diagnosing CRC patients with ctDNA sequencing technology.

Local and abscopal responses in advanced intrahepatic cholangiocarcinoma with low TMB, MSS, pMMR and negative PD-L1 expression following combined therapy of SBRT with PD-1 blockade.

BACKGROUND: Late-stage or recurrent intrahepatic cholangiocarcinoma (ICC) patients exhibit poor prognosis due to limited sensitivity to chemotherapy or radiotherapy and coexistence of multiple lesions. Programmed cell death protein 1 (PD-1) blockade provides a therapeutic opportunity for patients with high tumor mutation burden (TMB), high microsatellite instability (MSI-H), deficient mismatch repair (dMMR) and/or positive programmed cell death ligand 1 (PD-L1) expression. However, it is currently believed that patients with low TMB, microsatellite stable (MSS), proficient mismatch repair (pMMR) or negative PD-L1 expression are less likely to benefit from PD-1 blockade. CASE PRESENTATION: Here we provide the first report on the therapeutic responses of ICC patients treated with combined PD-1 blockade with stereotactic body radiotherapy (SBRT) (Cyberknife) in the background of low TMB, MSS, pMMR and negative PD-L1 expression. One stage IVA ICC patients and two postsurgical recurrent ICC patients were involved in this study and the responses of both locally irradiated tumor(s) and the abscopal tumors or metastasis to the combined therapy were assessed by magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT). The stage IVA ICC patient (patient A) exhibited a TMB of 1.2 muts/Mb with MSS, pMMR and < 1% PD-L1 expression. Both the intrahepatic lesion and the lymph node metastases were well controlled for 7 months, and partial response (PR) was achieved with the sum of lesion diameters decreased by 40.9%. One of the postsurgical recurrent ICC patients (Patient B) exhibited a TMB of 3.8 muts/Mb with MSS, pMMR and < 1% PD-L1 expression. Both the recurrent intrahepatic lesion and the lymph node metastases were well controlled by the combined therapy and the sum of lesion diameter decreased by 86.3% (PR). The other postsurgical recurrent patient (Patient C) exhibited a TMB of 0.98 muts/Mb with MSS, pMMR and < 1% PD-L1 expression, and achieved complete response (CR) and maintained for 11 months. Abscopal effects were observed for all three patients. CONCLUSIONS: This study provided the first set of evidence for the effectiveness of SBRT and PD-1 blockade combined therapy in late-stage or recurrent ICC patients with low TMB, MSS, pMMR and negative PD-L1 expression, and potentially expanded the indications of the combined therapy to those patients who were previously not suitable for immunotherapy.

GeneFuse: detection and visualization of target gene fusions from DNA sequencing data.

In recent years, gene fusion detection for cancer treatment has become increasingly important since more therapeutic agents have been developed to suppress fusion kinases. Although a number of tools have been developed to detect gene fusions from DNA sequencing data, most of them are not sensitive enough for processing the data from the samples with low tumor DNA composition, like cell-free tumor DNA. In this paper, we will introduce GeneFuse, a tool to detect and visualize gene fusions with high sensitivity and specificity. GeneFuse focuses on the curated gene fusions, which are available in COSMIC (the Catalogue of Somatic Mutations in Cancer) database. For each detected fusion, GeneFuse reports its genome locus, inferred protein forms, and supporting sequencing reads. The fusion detection results are visualized in an HTML page for cloud-friendly validation. GeneFuse is an open source tool available at GitHub: https://github.com/OpenGene/GeneFuse.

Detection of Urothelial Bladder Carcinoma via Microfluidic Immunoassay and Single-Cell DNA Copy-Number Alteration Analysis of Captured Urinary-Exfoliated Tumor Cells.

The increasing incidence of bladder cancer and its high rate of recurrence over a 5-year period necessitate the need for diagnosis and surveillance amelioration. Cystoscopy and urinary cytology are the current tools, and molecular techniques such as BTA stat, NMP22, survivin mRNA, and urovysion FISH have attracted attention; however, they suffer from insufficient sensitivity or specificity. We developed a novel microfluidic approach for harvesting intact urinary-exfoliated tumor cells (UETC), either individually or in clusters, in a clean and segregated environment, which is crucial to minimize cross-contamination and misreads. To reliably and accurately identify UETC, our quantitative immunoassay involved concurrent use of two oncoproteins CK20 and CD44v6 antigen. CK20 is an intermediate filament protein overexpressed in urothelial tumors, and CD44v6 is a membrane adhesion molecule closely associated with cell invasion, tumor progression, and metastatic spread. Single-cell whole-genome sequencing on 12 captured UETCs and copy number alteration analysis showed that 11/12 (91.7%) of the immunofluorescence-identified UETCs possessed genomic instability. A total of 79 patients with bladder cancer and 43 age-matched normal controls (NC) were enrolled in the study. We detected considerably higher UETC counts in patients with bladder cancer versus the NC group [53.3 (10.7-1001.9) vs. 0.0 (0-3.0) UETCs/10 mL; P < 0.0001]. For bladder cancer detection, a stratified 10-fold cross-validation of training data reveals an overall predictive accuracy of 0.84 [95% confidence interval (CI), 0.76-0.93] with an 89.8% (95% CI, 71.5%-86.4%) for sensitivity and 71.5% (95% CI, 59.7%-83.3%) for specificity. Overall, the microfluidic immunoassay demonstrates increased sensitivity and specificity compared with other techniques for the detection of bladder cancer.Significance: A unique and promising diagnostic assay for bladder cancer is proposed with potential clinical utility as a complement for cytology. Cancer Res; 78(14); 4073-85. ©2018 AACR.

Sequencing of circulating tumor DNA for dynamic monitoring of gene mutations in advanced non-small cell lung cancer.

Lung cancer is the most commonly occurring type of cancer worldwide and also has the highest mortality rate. Although targeted therapy of non-small cell lung carcinoma (NSCLC) has become common, the majority of patients receiving first-line epithelial growth factor receptor (EGFR)-TKI treatment develop drug resistance. The EGFR T790M (NM_005228.4(EGFR):c.2369C>T (p.Thr790Met)) mutation accounts for half of all reported resistance cases; however, the molecular mechanism resulting in the drug resistance remains to be characterized. Circulating tumor DNA (ctDNA) isolated from plasma has great potential for identification of gene mutations in NSCLC. Collection of ctDNA is relatively non-invasive and can avoid the inherent disadvantages of tissue biopsy. In the present study, next-generation sequencing technology was used to detect the variation of ctDNA in the peripheral blood of patients administered with EGFR-TKI. The patients were monitored serially to establish a dynamic resistance gene detection system, with the rationale being to alter the treatment strategy as soon as the emergence of drug resistance gene mutations. A mutation spectrum of the group of patients was constructed. A driver gene mutation was identified in the ctDNA of each patient, and certain patients had clinically targetable gene mutations like EGFR, ROS proto-oncogene receptor tyrosine kinase and B-Raf proto-oncogene serine/threonine kinase. The dynamic monitoring of EGFR status indicated that the EGFR mutation rate was consistent with the tumor burden of patients. Overall, ctDNA detection is a useful method for the molecular genotyping of patients with cancer. The dynamic resistance gene detection system described in the present study is a sensitive and useful tool for the monitoring of gene status, which has potential to be used for direction of treatment strategy by detecting the emergence of drug resistance gene mutations.

Monitoring colorectal cancer following surgery using plasma circulating tumor DNA.

Postoperative monitoring for patients with colorectal cancer (CRC) requires sensitive biomarkers that are associated with medical response and adjuvant therapy following surgery. Conventional tumor biomarkers [including carcinoembryonic antigen (CEA), CA19-9 and CA125] are widely used, but none of the markers provide high sensitivity or specificity. Previous studies indicated that circulating tumor DNA (ctDNA) is useful for postoperative monitoring of patients with cancer. However, the majority of previous studies involved patients with lung cancer, and therefore further studies are required which investigate patients with CRC. The present study enrolled 11 patients with CRC. All patients underwent surgery, and a number of patients were treated with postoperative chemotherapy. Tumor tissues and serial blood samples were collected from each patient, and somatic mutations of each sample were obtained using next-generation sequencing. The mutation landscape and dynamic changes in mutations for each patient were analyzed, and these results were compared with the changes of CEA levels. A number of driver genes were selected, including tumor protein P53 (TP53), APC and KRAS, to monitor the postoperative outcome of the 11 patients with CRC. Driver mutations were detected in preoperative plasma in 7 patients, with markedly decreased mutation rates detected in postoperative plasma compared with preoperative plasma. Driver mutations were not detected in 4 patients in the preoperative or postoperative plasma. In 1 patient with metastatic rectal cancer, the rate of TP53 mutation increased from 8.95 (preoperative) to 71.4% (postoperative), and a new phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α mutation emerged. This patient succumbed to mortality six months following surgery, however there were no marked changes in CEA levels during periodic detection of CEA levels. In summary, ctDNA has a high sensitivity and specificity in prediction of the prognosis of patients with CRC.

MutScan: fast detection and visualization of target mutations by scanning FASTQ data.

BACKGROUND: Some types of clinical genetic tests, such as cancer testing using circulating tumor DNA (ctDNA), require sensitive detection of known target mutations. However, conventional next-generation sequencing (NGS) data analysis pipelines typically involve different steps of filtering, which may cause miss-detection of key mutations with low frequencies. Variant validation is also indicated for key mutations detected by bioinformatics pipelines. Typically, this process can be executed using alignment visualization tools such as IGV or GenomeBrowse. However, these tools are too heavy and therefore unsuitable for validating mutations in ultra-deep sequencing data. RESULT: We developed MutScan to address problems of sensitive detection and efficient validation for target mutations. MutScan involves highly optimized string-searching algorithms, which can scan input FASTQ files to grab all reads that support target mutations. The collected supporting reads for each target mutation will be piled up and visualized using web technologies such as HTML and JavaScript. Algorithms such as rolling hash and bloom filter are applied to accelerate scanning and make MutScan applicable to detect or visualize target mutations in a very fast way. CONCLUSION: MutScan is a tool for the detection and visualization of target mutations by only scanning FASTQ raw data directly. Compared to conventional pipelines, this offers a very high performance, executing about 20 times faster, and offering maximal sensitivity since it can grab mutations with even one single supporting read. MutScan visualizes detected mutations by generating interactive pile-ups using web technologies. These can serve to validate target mutations, thus avoiding false positives. Furthermore, MutScan can visualize all mutation records in a VCF file to HTML pages for cloud-friendly VCF validation. MutScan is an open source tool available at GitHub: https://github.com/OpenGene/MutScan.