Molecular characterization and biomarker identification in paediatric B-cell acute lymphoblastic leukaemia.

B-cell acute lymphoblastic leukaemia (B-ALL) is the most prevalent hematologic malignancy in children and a leading cause of mortality. Managing B-ALL remains challenging due to its heterogeneity and relapse risk. This study aimed to delineate the molecular features of paediatric B-ALL and explore the clinical utility of circulating tumour DNA (ctDNA). We analysed 146 patients with paediatric B-ALL who received systemic chemotherapy. The mutational landscape was profiled in bone marrow (BM) and plasma samples using next-generation sequencing. Minimal residual disease (MRD) testing on day 19 of induction therapy evaluated treatment efficacy. RNA sequencing identified gene fusions in 61% of patients, including 37 novel fusions. Specifically, the KMT2A-TRIM29 novel fusion was validated in a boy who responded well to initial therapy but relapsed after 1 year. Elevated mutation counts and maximum variant allele frequency in baseline BM were associated with significantly poorer chemotherapy response (p = 0.0012 and 0.028, respectively). MRD-negative patients exhibited upregulation of immune-related pathways (p < 0.01) and increased CD8+ T cell infiltration (p = 0.047). Baseline plasma ctDNA exhibited high mutational concordance with the paired BM samples and was significantly associated with chemotherapy efficacy. These findings suggest that ctDNA and BM profiling offer promising prognostic insights for paediatric B-ALL management.

Circulating tumor DNA assisting lymphoma genetic feature profiling and identification.

INTRODUCTION: Lymphoma tissue biopsies cannot fully capture genetic features due to accessibility and heterogeneity. We aimed to assess the applicability of circulating tumor DNA (ctDNA) for genomic profiling and disease surveillance in classic Hodgkin lymphoma (cHL), primary mediastinal large B-cell lymphoma (PMBCL), and diffuse large B-cell lymphoma (DLBCL). METHODS: Tumor tissue and/or liquid biopsies of 49 cHLs, 32 PMBCLs, and 74 DLBCLs were subject to next-generation sequencing targeting 475 genes. The concordance of genetic aberrations in ctDNA and paired tissues was investigated, followed by elevating ctDNA-based mutational landscapes and the correlation between ctDNA dynamics and radiological response/progression. RESULTS: ctDNA exhibited high concordance with tissue samples in cHL (78%), PMBCL (84%), and DLBCL (78%). In cHL, more unique mutations were detected in ctDNA than in tissue biopsies (P < 0.01), with higher variant allele frequencies (P < 0.01). Distinct genomic features in cHL, PMBCL, and DLBCL, including STAT6, SOCS1, BTG2, and PIM1 alterations, could be captured by ctDNA alone. Prevalent PD-L1/PD-L2 amplifications were associated with more concomitant alterations in PMBCL (P < 0.01). Moreover, ctDNA fluctuation could reflect treatment responses and indicate relapse before imaging diagnosis. CONCLUSIONS: Lymphoma genomic profiling by ctDNA was concordant with that by tumor tissues. ctDNA might also be applied in lymphoma surveillance.

Utilizing metagenomic next-generation sequencing for pathogen detection and diagnosis in lower respiratory tract infections in real-world clinical practice.

BACKGROUND: Infectious etiologies of lower respiratory tract infections (LRTIs) by the conventional microbiology tests (CMTs) can be challenging. Metagenomic next-generation sequencing (mNGS) has great potential in clinical use for its comprehensiveness in identifying pathogens, particularly those difficult-to-culture organisms. METHODS: We analyzed a total of 205 clinical samples from 201 patients with suspected LRTIs using mNGS in parallel with CMTs. mNGS results were used to guide treatment adjustments for patients who had negative CMT results. The efficacy of treatment was subsequently evaluated in these patients. RESULTS: mNGS-detected microorganisms in 91.7% (188/205) of the clinical samples, whereas CMTs demonstrated a lower detection rate, identifying microorganisms in only 37.6% (77/205) of samples. Compared to CMT results, mNGS exhibited a detection sensitivity of 93.5% and 95.4% in all 205 clinical samples and 180 bronchoalveolar lavage fluid (BALF) samples, respectively. A total of 114 patients (114/201; 56.7%) showed negative CMT results, among which 92 received treatment adjustments guided by their positive mNGS results. Notably, 67.4% (62/92) of patients demonstrated effective treatment, while 25% (23/92) experienced a stabilized condition. Subgroup analysis of cancer patients revealed that 41.9% (13/31) exhibited an effective response to treatment, and 35.5% (11/31) maintained a stable condition following medication adjustments guided by mNGS. CONCLUSION: mNGS demonstrated great potential in identifying microorganisms of clinical significance in LRTIs. The rapid turnaround time and reduced susceptibility to the impact of antimicrobial administration make mNGS a valuable supplementary tool for diagnosis and treatment decision-making for suspected LRTIs in clinical practice.

The clinical utility of plasma circulating tumor DNA in the diagnosis and disease surveillance in non-diffuse large B-cell non-Hodgkin lymphomas.

Aim: Advances in circulating tumor DNA (ctDNA) analysis for diffuse large B-cell lymphoma (DLBCL) have prompted the evaluation of its utility in other non-Hodgkin lymphomas (NHLs), leading to significant insights into its potential applications.Methods: We retrospectively studied paired plasma and tissue/bone marrow biopsies of 203 non-DLBCL NHLs [87 follicular lymphomas (FL), 64 mantle cell lymphomas (MCL), 30 chronic lymphocytic leukemia/small lymphocytic lymphomas (CLL/SLL) and 22 marginal zone lymphomas (MZL)]. Genomic profiling was performed using a targeted next generation sequencing panel (Hemasalus™). Longitudinal analyses were performed to explore plasma ctDNA utility in disease monitoring.Results: High plasma ctDNA detection rates were observed across NHL subtypes (FL: 88.5%, MCL: 90.6%, CLL/SLL: 100%, MZL: 68.2%), with high concordance of actionable mutations (FL: 87.4%, MCL: 93.8%, CLL/SLL: 93.3%, MZL: 81.8%) and multiple genetic aberrations exclusively identified in plasma. Particularly, IGH-BCL2 and IGH-CCND1 fusions were concordant between plasma and tumor biopsies in FLs (91.1%) and MCLs (91.3%), respectively. Longitudinal data demonstrated that ctDNA clearance correlated with complete response but ctDNA increases preceded radiological relapses.Conclusion: ctDNA exhibited high concordance with tumor biopsy in detecting genetic aberrations and demonstrated potential as a promising noninvasive approach to disease surveillance in non-DLBCL NHLs.

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Plasma extracellular vesicle transcriptomics identifies CD160 for predicting immunochemotherapy efficacy in lung cancer.

Better biomarkers are needed to improve the efficacy of immune checkpoint inhibitors in lung adenocarcinoma (LUAD) treatment. We investigated the plasma extracellular vesicle (EV)-derived long RNAs (exLRs) in unresectable/advanced LUAD to explore biomarkers for immunochemotherapy. Seventy-four LUAD patients without targetable mutations receiving first-line anti-programmed cell death 1 (PD-1) immunochemotherapy were enrolled. Their exLRs were profiled through plasma EV transcriptome sequencing. Biomarkers were analyzed against response rate and survival using pre- and post-treatment samples in the retrospective cohort (n = 36) and prospective cohort (n = 38). The results showed that LUAD patients demonstrated a distinct exLR profile from the healthy individuals (n = 56), and T-cell activation-related pathways were enriched in responders. Among T-cell activation exLRs, CD160 exhibited a strong correlation with survival. In the retrospective cohort, the high baseline EV-derived CD160 level correlated with prolonged progression-free survival (PFS) (P < 0.001) and overall survival (OS) (P = 0.005), with an area under the curve (AUC) of 0.784 for differentiating responders from non-responders. In the prospective cohort, the CD160-high patients also showed prolonged PFS (P = 0.003) and OS (P = 0.014) and a promising AUC of 0.648. The predictive value of CD160 expression was validated by real-time quantitative PCR. We also identified the dynamics of EV-derived CD160 for monitoring therapeutic response. The elevated baseline CD160 reflected a higher abundance of circulating NK cells and CD8+ -naïve T cells, suggesting more active host immunity. In addition, increased CD160 levels of tumors also correlated with a favorable prognosis in LUAD patients. Together, plasma EV transcriptome analysis revealed the role of the baseline CD160 level and early post-treatment CD160 dynamics for predicting the response to anti-PD-1 immunochemotherapy in LUAD patients.

Identification of TCR rearrangements specific for genetic alterations in EGFR-mutated non-small cell lung cancer: results from the ADJUVANT-CTONG1104 trial.

Tumor response T cells, which have specific T cell receptor (TCR) rearrangements in tumor-infiltrating lymphocytes, determine their ability to interact with the mutation-derived neoantigens presented by antigen-presenting cells. Little is known about the genetic alterations related to specific TCR clones in non-small cell lung cancer (NSCLC) patients who have an epidermal growth factor receptor (EGFR) mutation. In this study, tumor tissues were collected from 101 patients with stage II/III resectable NSCLC with an EGFR mutation (57 patients were treated with gefitinib and 44 were treated with chemotherapy) in the ADJUVANT-CTONG1104 trial for high-throughput TCRß V region and exome sequencing. Ten clonal TCRs were associated with EGFR exon 19 deletion (del), EGFR exon 21 mutation (L858R), RB1 alteration, TP53 exon 4/5 missense mutation, TP53 nonsense mutation, or copy number gains in NKX2-1 and CDK4. Among the TCRs, there was frequent use of Vß20-1Jß2-3 specifically for EGFR exon 19 del or Vß9Jß2-1 specifically for EGFR exon 21 mutation (L858R), and these were significantly associated with favorable overall survival (OS) for NSCLC patients harboring EGFR exon 19 del or exon 21 L858R, particularly in the adjuvant gefitinib setting. Moreover, in comparison with the chemotherapy-preferable (CP) group, higher frequencies of Vß20-1Jß2-3 and Vß9Jß2-1 were found in the highly TKI-preferable (HTP) or TKI-preferable (TP) groups. Altogether, we identified ten TCR rearrangements specific for genetic alterations in NSCLC. Importantly, high abundance Vß20-1Jß2-3 or Vß9Jß2-1 may be an immune biomarker for guiding adjuvant gefitinib decisions for NSCLC patients harboring EGFR exon 19 del or EGFR exon 21 L858R.

Rare mutation-dominant compound EGFR-positive NSCLC is associated with enriched kinase domain-resided variants of uncertain significance and poor clinical outcomes.

BACKGROUND: Compound epidermal growth factor receptor (EGFR) mutations are less responsive to tyrosine kinase inhibitors (TKIs) than single EGFR mutations in non-small cell lung cancer (NSCLC). However, the detailed clinical characteristics and prognosis of various compound EGFR mutations remain to be elucidated. METHODS: We retrospectively studied the next-generation sequencing (NGS) data of treatment-naïve tumors from 1025 NSCLC patients with compound EGFR mutations, which were sub-categorized into different combinations of common mutations (19-Del and EGFR exon 21 p.L858R), rare mutations, and variants of uncertain significance (VUSs). Prognosis and drug resistance to first-line TKIs were analyzed in 174 and 95 patients, respectively. RESULTS: Compound EGFR mutations were enriched with EGFR exon 21 p.L858R and rare mutations, but not 19-Del (P < 0.001). The common + rare and rare + rare subtypes had fewer concurrent mutations in the PI3K pathway (P = 0.032), while the rare + rare and common + VUSs subtypes showed increased association with smoking- and temozolomide-related mutational signatures, respectively (P < 0.001). The rare mutation-dominant subtypes (rare + VUSs and rare + rare) had the worst clinical outcomes to first-line TKIs (P < 0.001), which was further confirmed using an external cohort (P = 0.0066). VUSs in the rare + VUSs subtype selectively reside in the EGFR kinase domain (P < 0.001), implying these tumors might select additional mutations to disrupt the regulation/function of the kinase domain. CONCLUSIONS: Different subtypes of compound EGFR mutations displayed distinct clinical features and genetic architectures, and rare mutation-dominant compound EGFR mutations were associated with enriched kinase domain-resided VUSs and poor clinical outcomes. Our findings help better understand the oncogenesis of compound EGFR mutations and forecast prognostic outcomes of personalized treatments.

The enrichment of Fanconi anemia/homologous recombination pathway aberrations in ATM/ATR-mutated NSCLC was accompanied by unique molecular features and poor prognosis.

BACKGROUND: ATM and ATR are two critical factors to regulate DNA damage response (DDR), and their mutations were frequently observed in different types of cancer, including non-small cell lung cancer (NSCLC). Given that the majority of identified ATM/ATR mutations were variants of uncertain significance, the clinical/molecular features of pathogenic ATM/ATR aberrations have not been comprehensively investigated in NSCLC. METHODS: Next-generation sequencing (NGS) analyses were conducted to investigate the molecular features in 191 NSCLC patients who harbored pathogenic/likely pathogenic ATM/ATR mutations and 308 NSCLC patients who did not have any types of ATM/ATR variants. The results were validated using an external cohort of 2727 NSCLC patients (including 48 with ATM/ATR pathogenic mutations). RESULTS: Most pathogenic ATM/ATR genetic alterations were frameshift and nonsense mutations that disrupt critical domains of the two proteins. ATM/ATR-mutated patients had significantly higher tumor mutational burdens (TMB; P < 0.001) and microsatellite instabilities (MSI; P = 0.023), but not chromosomal instabilities, than those without any ATM/ATR variations. In particular, KRAS mutations were significantly enriched in ATM-mutated patients (P = 0.014), whereas BRCA2 mutations (P = 0.014), TP53 mutations (P = 0.014), and ZNF703 amplification (P = 0.008) were enriched in ATR-mutated patients. Notably, patients with ATM/ATR pathogenic genetic alterations were likely to be accompanied by mutations in Fanconi anemia (FA) and homologous recombination (HR) pathways, which were confirmed using both the study (P < 0.001) and validation (P < 0.001) cohorts. Furthermore, the co-occurrence of FA/HR aberrations could contribute to increased TMB and MSI, and patients with both ATM/ATR and FA/HR mutations tended to have worse overall survival. CONCLUSIONS: Our results demonstrated the unique clinical and molecular features of pathogenic ATM/ATR mutations in NSCLC, which helps better understand the cancerous involvement of these DDR regulators, as well as directing targeted therapies and/or immunotherapies to treat ATM/ATR-mutated NSCLC, especially those with co-existing FA/HR aberrations.

Simultaneous diagnosis of tuberculous pleurisy and malignant pleural effusion using metagenomic next-generation sequencing (mNGS).

BACKGROUND: Metagenomic next-generation sequencing (mNGS) has become a powerful tool for pathogen detection, but the value of human sequencing reads generated from it is underestimated. METHODS: A total of 138 patients with pleural effusion (PE) were diagnosed with tuberculous pleurisy (TBP, N = 82), malignant pleural effusion (MPE, N = 35), or non-TB infection (N = 21), whose PE samples all underwent mNGS analysis. Clinical TB tests including culture, Acid-Fast Bacillus (AFB) test, Xpert, and T-SPOT, were performed. To utilize mNGS for MPE identification, 25 non-MPE samples (20 TBP and 5 non-TB infection) were randomly selected to set human chromosome copy number baseline and generalized linear modeling was performed using copy number variant (CNV) features of the rest 113 samples (35 MPE and 78 non-MPE). RESULTS: The performance of TB detection was compared among five methods. T-SPOT demonstrated the highest sensitivity (61% vs. culture 32%, AFB 12%, Xpert 35%, and mNGS 49%) but with the highest false-positive rate (10%) as well. In contrast, mNGS was able to detect TB-genome in nearly half (40/82) of the PE samples from TBP subgroup, with 100% specificity. To evaluate the performance of using CNV features of the human genome for MPE prediction, we performed the leave-one-out cross-validation (LOOCV) in the subcohort excluding the 25 non-MPE samples for setting copy number standards, which demonstrated 54.1% sensitivity, 80.8% specificity, 71.7% accuracy, and an AUC of 0.851. CONCLUSION: In summary, we exploited the value of human and non-human sequencing reads generated from mNGS, which showed promising ability in simultaneously detecting TBP and MPE.

Genomic alterations of cerebrospinal fluid cell-free DNA in leptomeningeal metastases of gastric cancer.

BACKGROUND: Leptomeningeal metastases (LM) were rare in gastric cancer (GC), and GC patients with LM (GCLM) generally suffer from poor prognosis. Nevertheless, the clinical utility of cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) was underinvestigated in GCLM. METHODS: We retrospectively studied 15 GCLM patients, and all patients had paired primary tumor tissue samples and post-LM CSF samples while 5 patients also had post-LM plasma samples. All samples were analyzed using next-generation sequencing (NGS), and the molecular and clinical features were correlated with clinical outcomes. RESULTS: CSF had higher mutation allele frequency (P = 0.015), more somatic mutations (P = 0.032), and more copy-number variations (P < 0.001) than tumor or plasma samples. Multiple genetic alterations and aberrant signal pathways were enriched in post-LM CSF, including CCNE1 amplification and cell cycle-related genes, and CCNE1 amplification was significantly associated with patients' overall survival (P = 0.0062). More potential LM progression-related markers were detected in CSF samples than in tumor samples, including PREX2 mutation (P = 0.014), IGF1R mutation (P = 0.034), AR mutation (P = 0.038), SMARCB1 deletion (P < 0.001), SMAD4 deletion (P = 0.0034), and TGF-beta pathway aberration (P = 0.0038). Additionally, improvement in intracranial pressure (P < 0.001), improvement in CSF cytology (P = 0.0038), and relatively low levels of CSF ctDNA (P = 0.0098) were significantly associated with better PFS. Lastly, we reported a GCLM case whose CSF ctDNA dynamic changes were well correlated with his clinical assessment. CONCLUSIONS: CSF ctDNA could more sensitively detect molecular markers and metastasis-related mechanisms than tumor tissues in GCLM patients, and our study sheds light on utilizing CSF ctDNA in prognostic estimation and clinical assessment in GCLM.

Mutations in the MET tyrosine kinase domain and resistance to tyrosine kinase inhibitors in non-small-cell lung cancer.

BACKGROUND: The Mesenchymal epithelial transition factor (MET) gene encodes a receptor tyrosine kinase with pleiotropic functions in cancer. MET exon 14 skipping alterations and high-level MET amplification are oncogenic and targetable genetic changes in patients with non-small-cell lung cancer (NSCLC). Resistance to tyrosine kinase inhibitors (TKIs) has been a major challenge for targeted therapies that impairs their clinical efficacies. METHODS: Eighty-six NSCLC patients were categorized into three cohorts based on the time of detecting MET tyrosine kinase domain (TKD) mutations (cohort 1: at baseline; cohort 2: after MET-TKI treatment; cohort 3: after EGFR-TKI treatment). Baseline and paired TKI treatment samples were analyzed by targeted next-generation sequencing. RESULTS: MET TKD mutations were highly prevalent in METex14-positive NSCLC patients after MET-TKI treatment, including L1195V, D1228N/H/Y/E, Y1230C/H/N/S, and a double-mutant within codons D1228 and M1229. Missense mutations in MET TKD were also identified at baseline and in post-EGFR-TKI treatment samples, which showed different distribution patterns than those in post-MET-TKI treatment samples. Remarkably, H1094Y and L1195F, absent from MET-TKI-treated patients, were the predominant type of MET TKD mutations in patients after EGFR-TKI treatment. D1228H, which was not found in treatment-naïve patients, also accounted for 14.3% of all MET TKD mutations in EGFR-TKI-treated samples. Two patients with baseline EGFR-sensitizing mutations who acquired MET-V1092I or MET-H1094Y after first-line EGFR-TKI treatment experienced an overall improvement in their clinical symptoms, followed by targeted therapy with MET-TKIs. CONCLUSIONS: MET TKD mutations were identified in both baseline and patients treated with TKIs. MET-H1094Y might play an oncogenic role in NSCLC and may confer acquired resistance to EGFR-TKIs. Preliminary data indicates that EGFR-mutated NSCLC patients who acquired MET-V1092I or MET-H1094Y may benefit from combinatorial therapy with EGFR-TKI and MET-TKI, providing insights into personalized medical treatment.

The differences in immune features and genomic profiling between squamous cell carcinoma and adenocarcinoma - A multi-center study in Chinese patients with uterine cervical cancer.

BACKGROUND: Squamous cell carcinoma (SCC) and adenocarcinoma (AC) of the uterine cervix have distinct biological behaviors and different treatment responses. Studies on immune features and genomic profiling of these two pathologic types were limited and mainly focused on small patient cohorts. METHODS: From 2014 to 2021, 336 (254 SCC vs. 82 AC) cervical cancer patients who were diagnosed/treated in 7 medical centers in China were enrolled in the study. Next-generation sequencing of 425 cancer-relevant genes was performed on tumor tissues and liquid biopsies. Somatic alterations and immune response-related biomarkers were analyzed. Patient prognosis and immune infiltration were analyzed using data from The Cancer Genome Atlas (TCGA). RESULTS: AC tended to have more immunotherapy resistance-related STK11 alterations (P = 0.039), a higher proportion of microsatellite instability (P = 0.21), and more actionable mutations (P = 0.161). In contrast, higher tumor mutational burdens (TMB; P = 0.01), a higher proportion of TMB-high patients (P = 0.016), and more PD-L1-high patients (P = 0.0013) were observed in SCC. Multiple genetic alterations and aberrant signaling pathways were specifically enriched in AC (e.g., TP53, KRAS, ERBB2, and ARID1A alterations) or SCC (e.g., PIK3CA, FBXW7, EP300, and BAP1 mutations). Notably, AC-enriched genetic changes were significantly associated with decreased infiltrations of various B cells, T cells, and dendritic cells, whereas SCC-associated molecular features tended to be associated with increased CD4+ T cell infiltrations. CONCLUSIONS: This was the first multi-center study revealing the immunologic and genomic features between SCC and AC in Chinese patients with cervical cancer. Our findings have illustrated the difference in genetic profiles of those two cervical cancer subtypes, which may suggest the possibility of differential treatment regimens, with better immunotherapy efficacy in SCC and targeted therapy options more favorable in AC.

Dynamic monitoring of cerebrospinal fluid circulating tumor DNA to identify unique genetic profiles of brain metastatic tumors and better predict intracranial tumor responses in non-small cell lung cancer patients with brain metastases: a prospective cohort study (GASTO 1028).

BACKGROUND: Due to the blood-brain barrier, plasma is not an ideal source to evaluate the genetic characteristics of central nervous system tumors. Thus, cerebrospinal fluid (CSF) is becoming an alternative biopsy type to evaluate the genetic landscape of intracranial tumors. We aimed to explore the genetic profiles of CSF-derived circulating tumor DNA (ctDNA) to predict intracranial tumor responses and monitor mutational evolution during the treatment of non-small cell lung cancer (NSCLC) patients with brain metastases. METHODS: We conducted a prospective study of 92 newly diagnosed NSCLC patients with brain metastases. Paired CSF and plasma samples were collected at baseline, 8 weeks after treatment initiation, and disease progression. All samples underwent next-generation sequencing of 425 cancer-related genes. RESULTS: At baseline, the positive detection rates of ctDNA in CSF, plasma, and extracranial tumors were 63.7% (58/91), 91.1% (82/90), and 100% (58/58), respectively. A high level of genetic heterogeneity was observed between paired CSF and plasma, while concordance in driver mutations was also observed. A higher number of unique copy number variations was detected in CSF-ctDNA than in plasma. ctDNA positivity of CSF samples at baseline was associated with poor outcomes (HR=2.565, P=0.003). Moreover, patients with ≥ 50% reductions in the concentrations of CSF ctDNA after 8 weeks of treatment had significantly longer intracranial progression-free survivals (PFS) than patients with < 50% reductions in CSF ctDNA concentrations (13.27 months vs 6.13 months, HR=0.308, P=0.017). A ≥ 50% reduction in CSF ctDNA concentrations had better concordance with radiographic intracranial tumor responses than plasma. A ≥ 50% reduction in plasma ctDNA concentrations was also associated with longer extracranial PFS (11.57 months vs 6.20 months, HR=0.406, P=0.033). Based on clonal evolution analyses, the accumulation of subclonal mutations in CSF ctDNA was observed after 8 weeks of treatment. The clonal mutations that remained in more than 80% in CSF after 8 weeks also predicted shorter intracranial PFS (HR=3.785, P=0.039). CONCLUSIONS: CSF ctDNA exhibited unique genetic profiles of brain metastases, and dynamic changes in CSF ctDNA could better predict intracranial tumor responses and track clonal evolution during treatment in NSCLC patients with brain metastases. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03257735.

RET fusions as primary oncogenic drivers and secondary acquired resistance to EGFR tyrosine kinase inhibitors in patients with non-small-cell lung cancer.

BACKGROUND: RET fusions are rare oncogenic drivers in non-small cell lung cancer (NSCLC). While activating RET rearrangements are found in NSCLC patients harboring epidermal growth factor receptor (EGFR) genetic alterations at resistance to EGFR inhibitors, the extent to which co-occurring genomic alterations exist and how they might affect prognosis or therapy response is poorly understood. METHODS: Targeted next-generation sequencing (NGS) was used to assess 380 baseline patients with primary RET fusions and 71 EGFR-mutated NSCLC patients who acquired RET fusions after developing resistance to EGFR-tyrosine kinase inhibitors (EGFR-TKIs). RESULTS: Primary RET fusions were more likely associated with females and younger age, with KIF5B being the predominant fusion partner. In baseline patients, both SMAD4 (5.3% vs. 0.0%, P = 0.044) and MYC copy-number gain variants (6.9% vs. 0.0%, P = 0.009) were more frequently co-mutated with KIF5B-RET than CCDC6-RET. By contrast, CDKN2A (11.3% vs. 2.4%, P = 0.003) mutations were significantly enriched in CCDC6-RET-rearranged baseline patients. A significant increase in the proportion of CCDC6-RET was observed in acquired RET-rearranged patients (47.3% vs. 22.5%, P < 0.001). The median progression-free survival (PFS) of patients harboring RB1 and TP53 double-mutations (5.5 vs. 10.0 months, P = 0.020) or ERBB2 amplification (5.6 vs. 10.0 months, P = 0.041) was significantly shorter than the wild-type counterparts. Moreover, we identified that RET fusions were more likely associated with acquired resistance (AR) to third-generation EGFR-TKIs than previous generations of EGFR-TKIs. CONCLUSIONS: In conclusion, we depicted the mutational profiles of NSCLC patients who harbor RET fusions at baseline or after resistance to EGFR-TKIs. Furthermore, our results suggest that RET fusions mediate secondary resistance to third-generation EGFR-TKIs and might be associated with poor prognosis in patients with NSCLC.

Clinical utility of cerebrospinal fluid-derived circular RNAs in lung adenocarcinoma patients with brain metastases.

BACKGROUND: Free circular RNAs(circRNAs) escaping from primary lesion of cancer to brain are strictly regulated by blood-brain barrier and therefore cerebrospinal fluid (CSF) circRNAs have potential advantage in exploring biomarkers and mechanism of brain metastasis in lung cancer. METHODS: We collected paired cerebrospinal fluid, plasma and tumor tissues from 21 lung adenocarcinoma (ADC) patients with brain metastases (BM) and performed RNA sequencing. RESULTS: Compared to tumor tissue and plasma, circRNAs in CSF were characterized by lower number of spieces but higher abundance. Notably, CSF-circRNAs displayed high heterogeneity among different BM lung ADC patients. A total of 60 CSF-circRNAs was identified and associated with shorten overall survival. The circRNA-miRNA-mRNA network analysis revealed that the 60 CSF-circRNAs involved in cancer-associated pathways, and five of them showed strong association with WNT signaling pathway. Validation by RT-PCR of CSF and in vitro experiments of the five candidate circRNAs support their potential roles in cell proliferation and invasion. CONCLUSIONS: In summary, our results depicted the heterogenous CSF-circRNAs profiles among BM lung ADC and implied that CSF-circRNAs may be promising prognosis-related biomarkers.

A pilot study of the use of dynamic analysis of cell-free DNA from aqueous humor and vitreous fluid for the diagnosis and treatment monitoring of vitreoretinal lymphomas.

The diagnosis of vitreoretinal lymphoma (VRL), a rare subtype of primary central nervous system lymphoma, is challenging. We aimed to investigate the mutational landscape of VRL by sequencing circulating tumor DNA (ctDNA) from aqueous humor (AH) and/or vitreous fluid (VF), as well as applying ctDNA sequencing to diagnosis and treatment monitoring. Baseline AH and/or VF specimens from 15 VRL patients underwent comprehensive genomic profiling using targeted next-generation sequencing. The molecular profiles of paired baseline AH and VF specimens were highly concordant, with comparable allele frequencies. However, the genetic alterations detected in cerebrospinal fluid ctDNA only partially overlapped with those from simultaneously collected AH/VF samples, with much lower allele frequencies. Serial post-treatment AH or VF samples were available for five patients and their changes in ctDNA allele frequency displayed a similar trend as the changes in interleukin-10 levels; an indicator of response to treatment. A cohort of 23 patients with primary central nervous system lymphoma was included as a comparison group for the genetic landscape and evaluations of the efficacy of ibrutinib. More MYD88 mutations, but fewer IRF4 mutations and CDKN2A/B copy number losses were observed in the baseline samples of primary central nervous system lymphoma than VRL patients. The objective response rate to ibrutinib treatment was much higher for patients with primary central nervous system lymphoma (64.7%, 11/17) than for those with VRL (14.3%, 1/7). In summary, we provide valuable clinical evidence that AH is a good source of tumor genomic information and can substitute VF. Moreover, molecular profiling of AH has clinical utility for the diagnosis of VRL and treatment monitoring.

Homologous recombination deficiency in diverse cancer types and its correlation with platinum chemotherapy efficiency in ovarian cancer.

BACKGROUND: Homologous recombination deficiency (HRD) is a molecular biomarker for administrating PARP inhibitor (PARPi) or platinum-based (Pt) chemotherapy. The most well-studied mechanism of causing HRD is pathogenic BRCA1/2 mutations, while HRD phenotype is also present in patients without BRCA1/2 alterations, suggesting other unknown factors. METHODS: The targeted next-generation sequencing (GeneseeqPrime® HRD) was used to evaluate the HRD scores of 199 patients (Cohort I). In Cohort II, a total of 85 Pt-chemotherapy-treated high-grade serous ovarian cancer (HGSOC) patients were included for investigating the role of HRD score in predicting treatment efficacy. The concurrent genomic features analyzed along HRD score evaluation were studied in a third cohort with 416 solid tumor patients (Cohort III). RESULTS: An HRD score ≥ 38 was predefined as HRD-positive by analyzing Cohort I (range: 0-107). Over 95% of the BRCA1/2-deficient cases of Cohort I were HRD-positive under this threshold. In Cohort II, Pt-sensitive patients have significantly higher HRD scores than Pt-resistant patients (median: 54 vs. 34, p = 0.031) and a significantly longer PFS was observed in HRD-positive patients (median: 548 vs. 343 days, p = 0.003). Furthermore, TP53, NCOR1, and PTK2 alterations were enriched in HRD-positive patients. In Cohort III, impaired homologous recombination repair pathway was more frequently observed in HRD-positive patients without BRCA1/2 pathogenic mutations. The alteration enrichment of TP53, NCOR1, and PTK2 observed in Cohort II was also validated by the ovarian subgroup in Cohort III. CONCLUSIONS: Using an in-house HRD evaluation method, our findings show that overall HRR gene mutations account for a significant part of HRD in the absence of BRCA1/2 aberrations, and suggest that HRD positive status might be a predictive biomarker of Pt-chemotherapy.

The genetic landscape of pancreatic head ductal adenocarcinoma in China and prognosis stratification.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is the major subtype of pancreatic cancer and head PDACs show distinct characteristics from body/tail PDACs. With limited studies based on Asian population, the mutational landscape of Asian PDAC remains unclear. METHODS: One hundred fifty-one Chinese patients with head PDAC were selected and underwent targeted 425-gene sequencing. Genomic alterations, tumor mutational burden, and microsatellite instability were analyzed and compared with a TCGA cohort. RESULTS: The genomic landscape of Chinese and Western head PDAC had identical frequently-mutated genes including KRAS, TP53, SMAD4, and CDKN2A. KRAS hotspot in both cohorts was codon 12 but Chinese PDACs containing more G12V but fewer G12R variants. Potentially pathogenic fusions, CHD2-BRAF and KANK1-MET were identified in two KRAS wild-type patients. Serum cancer antigens CA125 and CA19-9 were positively associated with SMAD4 alterations while high CEA was enriched in wild-type CDKN2A subgroup. The probability of vascular invasion was lower in patients with RNF43 alterations. The nomogram developed including histology grade, the mutation status of SMAD4, TGFBR2, and PREX2 could calculate the risk score of prognoses validated by Chinese and TCGA cohort. CONCLUSIONS: Chinese head PDAC contained more KRAS G12V mutation than Western population. The well-performed nomogram may improve post-operation care in real-world practice.

Comprehensive genomic profiling aids in understanding the lesion origins of a patient with six synchronous invasive lung adenocarcinomas: a case study.

BACKGROUND: Synchronous multiple primary lung cancers (sMPLC) are rare forms of lung cancer, and their diagnosis remains as a significant challenge. Distinguishing sMPLC from advanced disease is important as their prognoses and therapeutic management vary dramatically. CASE PRESENTATION: The patient was a 56-year-old Chinese male who exhibited six synchronous invasive adenocarcinomas at diagnosis [T2(6)N0M0], and who achieved durable clinical benefit under adjuvant chemotherapy for 41 months following wedge resection and lobectomy. Whole-exome sequencing revealed that two lesions (L4 and L6) in the left upper lobe of the patient's lung shared 28 nonsynonymous mutations; thus, suggesting that the lesions may have arisen from a common ancestor at the early stages of tumorigenesis, and spread into distinct histologic subtypes. Moreover, while L5 was in the same lobe as L4 and L6, it represented a distinct lineage as it did not share any mutations with other lesions. Notably, the BRAF V600E oncogenic mutation was exclusive to L5. In addition, the KRAS G12C mutation was identified in three lesions (L1-L3) located in the right lung, which may have resulted from convergent evolution. CONCLUSION: We report a patient with six synchronous invasive adenocarcinomas who demonstrated durable clinical benefits under adjuvant chemotherapy following surgical treatment. While cancer staging is one of the many challenges associated with sMPLC, the data generated through next-generation sequencing can provide information on lesion origins, and thus, advance the era of precision medicine.