Genomic features and tumor immune microenvironment alteration in NSCLC treated with neoadjuvant PD-1 blockade

Several clinical trials have shown the safety and effectiveness of PD-1/PD-L1 inhibitors in neoadjuvant therapy in resectable non-small cell lung cancer (NSCLC). However, 18–83% patients can benefit from it. In this study, we aimed to assess the association of PD-L1 expression, tumor mutation burden, copy number alteration (CNA, including copy number gain and loss) burden with the pathologic response to neoadjuvant PD-1 blockade and investigate the changes in the tumor immune microenvironment (TIME) during neoadjuvant immunotherapy in NSCLC. Pre-immunotherapy treatment tumor samples from twenty-nine NSCLC patients who received neoadjuvant immunotherapy with sintilimab, an anti-PD-1 drug, were subjected to targeted DNA sequencing and PD-L1 immunochemistry staining. The pathological response was positively correlated with tumor proportion score (TPS) of PD-L1 and negatively correlated with copy number gain (CNgain) burden. Of note, the combination of CNgain burden and TPS can better stratify major pathological response (MPR) patients than did CNgain or TPS alone. Whereas, TMB showed a limited correlation with pathological regression. Additionally, PD-1 blockade led to an increase in CD8+PD-1−T cells which was clinically relevant to MPR as evaluated by multiplex immunofluorescence. A significant reduction in CD19+ cells was observed in the Non-MPR group but not in the MPR group, indicating the involvement of B cells in improving neoadjuvant immunotherapy response in NSCLC. Together, our study provides new data for the correlation of PD-L1 expression and genomic factors with drug response in neoadjuvant immunotherapy settings in NSCLC. The changes of TIME may provide novel insight into the immune responses to neoadjuvant anti-PD-1 therapy.

Automated prediction of the clinical impact of structural copy number variations

Copy number variants (CNVs) play an important role in many biological processes, including the development of genetic diseases, making them attractive targets for genetic analyses. The interpretation of the effect of these structural variants is a challenging problem due to highly variable numbers of gene, regulatory, or other genomic elements affected by the CNV. This led to the demand for the interpretation tools that would relieve researchers, laboratory diagnosticians, genetic counselors, and clinical geneticists from the laborious process of annotation and classification of CNVs. We designed and validated a prediction method (ISV; Interpretation of Structural Variants) that is based on boosted trees which takes into account annotations of CNVs from several publicly available databases. The presented approach achieved more than 98% prediction accuracy on both copy number loss and copy number gain variants while also allowing CNVs being assigned “uncertain” significance in predictions. We believe that ISV’s prediction capability and explainability have a great potential to guide users to more precise interpretations and classifications of CNVs.

Correlation of MET-Receptor Overexpression with MET Gene Amplification and Patient Outcome in Malignant Mesothelioma

Thanks to clinically newly introduced inhibitors of the mesenchymal–epithelial transition (MET) receptor tyrosine-kinase, MET-gene copy number gain/amplification (MET-GCNG/GA) and increased expression of the MET protein are considered very promising therapeutic targets in lung cancer and other malignancies. However, to which extent these MET alterations occur in malignant mesothelioma (MM) remains unclear. Thus, we investigated by well-established immunohistochemistry and fluorescence in situ hybridization methods, the frequency of these alterations in specimens from 155 consecutive MMs of different subtypes obtained from pleural or peritoneal biopsies and pleurectomies. Thirty-three benign reactive mesothelial proliferations (RMPs) were used as controls. MET-protein upregulation was observed in 35% of all MM-cases, though restricted to predominantly epithelioid MMs. We detected low-/intermediate-level MET-GCNG/GA in 22.2% of MET-overexpressing MMs (7.8% of whole MM-cohort) and no MET-GCNG/GA in the other 77.8%, suggesting other upregulating mechanisms. In contrast, 100% of RMPs exhibited no MET-upregulation or MET-GCNG/-GA. Neither MET exon 14 skipping mutations nor MET-fusions were detected as mechanisms of MET overexpression in MM using RNA next-generation sequencing. Finally, in two cohorts of 30 MM patients with or without MET overexpression (MET-positive/-negative) that were matched for several variables and received the same standard chemotherapy, the MET-positive cases showed a significantly lower response rate, but no significant difference in progression-free or overall survival. Our results imply that MET overexpression occurs in a substantial fraction of predominantly epithelioid MMs, but correlates poorly with MET-amplification status, and may impact the likelihood of response to mesothelioma standard chemotherapy. The predictive significance of MET-IHC and -FISH for possible MET-targeted therapy of MM remains to be elucidated.

Integrated Epigenetic and Transcriptional Single Cell Analysis of t(11;14) Myeloma and Its BCL2 Dependency

Multiple myeloma is characterized by recurrent chromosomal translocations that involve the immunoglobulin gene enhancers and partners such as the cyclin D genes (CCND1, CCND2 or CCND3) or other genes like WHSC1 and MAF. t(11;14) results in upregulation of CCND1 with unique morphological, phenotypic markers, and drug sensitivity profiles with exquisite sensitivity to BCL2 inhibitors. It is evident now that this unique sensitivity profile is driven by the BH3-proapoptotic protein priming of BCL2 with high BCL2/MCL1 or BCL2/BCL2L1 ratios. However, the epigenetic mechanisms associated with t(11;14) and their impact on genes regulation and clinical response to venetoclax remains elusive. In the present study we compared the transcriptomics (scRNA-seq) and chromatin accessibility (scATAC-seq) of single plasma cells of MM patients with and without t(11;14) as well as pre- and post-venetoclax exposure in order to establish the epigenomic signature of t(11;14) and/or BCL2-sensitivity in myeloma. Serial BM aspirates (n=24) were collected from 15 relapsed or refractory myeloma patients (RRMM); harboring t(11;14) (n=6 pairs) and 9 without this translocation prior to initiation of salvage therapy and at time of relapse. All t(11;14) MM patients were treated with venetoclax. Unbiased chromatin accessibility and mRNA profiling of CD138 pos cells were performed using the chromium single cell ATAC and RNA-Seq 3' solution (10x Genomics), respectively. Cell Ranger, Seurat and ArchR were used for sample de-multiplexing, barcode processing, single-cell 3' gene, peaks counting, and data analysis. We first compared the scATAC-seq and scRNA-seq profiles found in CD138 pos MM cell isolated from patients harboring t(11;14) with the one obtained in patients without this translocation. As expected, t(11:14) patients had high chromatin accessibility at the CCND1 locus and high mRNA expression. Differentially accessible chromatin analysis identified 147518 peaks that were specific to t(11;14) patients. Of interest, motifs enrichment analysis of accessible peaks identified a "B cell-like" motifs signature with enriched TFs motifs such as TCF4 and PAX5 in t(11;14) patients compared to non t(11:14) enriched for IRF and STAT family of motifs. The integration of the scATAC-seq and scRNA-seq data confirmed the B cell signature of t(11;14) patients with upregulation of B cell markers such as MS4A1, VPREB3, CD79A, CD19, and down-regulation of plasma cell markers such as TDO2, EFEMP1, CD28, SLAMF7, and IL6R. Additionally, we found PAX1, PAX5, TCF3, TCF5, and SPI1 transcription factors to be highly expressed in t(11;14) while the non t(11:14) were enriched for IRF1-9 transcription factors. Of interest, the clustering analysis performed on scATAC-seq data identified 3 non t(11;14) patients with a chromatin accessibility profile similar to that of t(11;14) patients. They expressed B cell markers (PAX5, VPREB3 or FCRLA), overexpressed BCL2 and we are currently examining whether this B cell-like epigenetic signature determines sensitivity to venetoclax. In order to define the epigenetic contribution to the acquired resistance to venetoclax in t(11;14) myeloma, we compared the chromatin accessibility profiles of t(11;14) patients pre- vs. post-venetoclax treatment. Enriched motifs within accessible peaks differed significantly between pre- and post-venetoclax with RELA, REL, RELB and EGR1 motifs predominantly enrichmed in the pre-samples in contrast to JUN, JUNB, JUND and FOSL1/L2 motifs enrichment in the post-samples. Of note, integration analysis of scRNAseq (differentially expressed genes) and ATACseq data (differentially accessible peaks) identified MCL1 and ENSA (a gene 60 Kb centromeric to MCL1 on chr1q) as the top enriched genes and peaks in resistant samples suggesting that copy number gain at the MCL1 locus (which we confirmed by single cell CNV analysis) rather than epigenetic modifications is likely the main determinant of acquired resistant to venetoclax in t(11;14) MM. In the current study we have defined the epigenetic regulome and transcriptome associated with t(11;14) myeloma and its relatedness to B cell rather than plasma cell biology. Our studies also suggest that acquired resistance to venetoclax is largely driven by copy number gain at the MCL1 locus. Disclosures Bahlis: Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Genentech: Consultancy; Pfizer: Consultancy, Honoraria. Neri: BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria.

Comprehensive Genomic Profiling of Circulating Cell-Free DNA Distinguishes Focal MET Amplification from Aneuploidy in Diverse Advanced Cancers

Amplification (amp) of MET can be observed in cases of focal gene copy number gain, such as MET-driven amp, or with a gain of chromosome 7, such as aneuploidy. Several studies have shown that only high-level focal MET amp (MET/CEP7 ratio ≥5) is oncogenic, with such tumors responding to targeted therapy. However, there are few reports on how to distinguish between focal amplification and aneuploidy using next-generation sequencing (NGS). A total of 1025 patients with advanced solid tumors (typically pre-treated) were tested with a non-invasive comprehensive cfDNA NGS panel (Guardant360) from July 2014 to June 2019. Since bioinformatics upgrades of Guardant360 were undergoing in September 2018, focal MET amp was determined by our independent algorithm using the cohorts tested before September 2018 (291 patients), and validation was performed in the remaining cohort (734 patients). MET alterations (alts) associated with aberrant signaling were found in 110 patients (10.7%) among nine different cancer types, most commonly in non-small cell (12.2%, 62/510) and small cell (33.3%, 3/9) lung cancers, gastroesophageal cancer (19.4%, 7/36), and prostate adenocarcinoma (15.6%; 5/32). Among 291 patients tested before September 2018, 37 (12.7%) had MET alts. Among these, 24 (64.9%) had amps, 5 (13.5%) had exon 14 skipping, and 13 (35.1%) had single nucleotide variants (SNVs). Co-alterations, such as amp + SNVs, were found in four samples (10.8%). Among 24 MET amps, 29.2% (7/24) were focal according to our algorithm. MET copy number was significantly higher with focal amp compared to non-focal amp (mean copy number 3.26 vs. 2.44, respectively, p = 0.00304). In 734 patients tested after September 2018, our definition of focal MET amp was detected in 4.2% (31/734). Overall, focal amplification based on our algorithm was 3.7% (=38/1025). This study describes an approach to distinguish focal and non-focal MET amplification using comprehensive genomic profiling of cfDNA in advanced cancer patients. Focal MET amp accounted for ~30% of all MET amp, which was found in 3.7% of patients with diverse cancers and was associated with a higher plasma copy number. Clinical studies are warranted to assess the clinical utility of targeted therapies for tumors with focal MET amplification detected by NGS of cfDNA.

A new case of 17p13.3p13.1 microduplication resulted from unbalanced translocation: clinical and molecular cytogenetic characterization

Copy number gain 17 p13.3p13.1 was detected by chromosomal microarray (CMA) in a girl with developmental/speech delay and facial dysmorphism. FISH studies made it possible to establish that the identified genomic imbalance is the unbalanced t(9;17) translocation of maternal origin. Clinical features of the patient are also discussed. The advisability of using the combination of CMA and FISH analysis is shown. Copy number gains detected by clinical CMA should be confirmed using FISH analysis in order to determine the physical location of the duplicated segment. Parental follow-up studies is an important step to determine the origin of genomic imbalance. This approach not only allows a most comprehensive characterization of an identified chromosomal/genomic imbalance but also provision of an adequate medical and genetic counseling for a family taking into account a balanced chromosomal rearrangement.

High SPAG5 Expression Is Associated With Oncological Features in Endometrial Carcinoma

Sperm-associated Antigen 5 (SPAG5, also called astrin) is a mitotic spindle protein. SPAG5 has emerged as a promising biomarker and therapeutic target in a variety of cancers. However, its expression and role in endometrial cancer (EC) remain to be studied. Using multi-omic authoritative datasets from the TCGA and CPTAC studies, we characterized theexpression, regulation of SPAG5 and its association with clinicopathological and molecular features in EC. SPAG5 was observed to be overexpressed in tumor tissues compared to controls and receiver operating characteristic analysis suggested that its mRNA levels are an excellent predictor of tumor presence (AUC>0.98). SPAG5 overexpression was associated with serous histology and The Cancer Genome Atlas (TCGA) defined molecular subtypes. Analysis of DNA methylation levels at SPAG5 genomic regions exhibiting negative correlation to SPAG5 expression. Further, SPAG5 expression was associated with copy number gain in EC. Univariate and multivariate survival analysis revealed that higher SPAG5 expression was independently associated with poor patient outcomes in EC. Additionally, gene set enrichment analysis of SPAG5 correlated genes revealed its association with numerous oncological pathways which suggest its critical involvement in this malignancy.

NGS Analysis Confirms Common TP53 and RB1 Mutations, and Suggests MYC Amplification in Ocular Adnexal Sebaceous Carcinomas

Ocular adnexal (OA) sebaceous carcinomas generally demonstrate more aggressive clinical and histopathological phenotypes than extraocular cases, but the molecular drivers implicated in their oncogenesis remain poorly defined. A retrospective review of surgical and ocular pathology archives identified eleven primary resection specimens of OA sebaceous carcinomas with adequate tissue for molecular analysis; two extraocular cases were also examined. Next-generation sequencing was used to evaluate mutations and copy number changes in a large panel of cancer-associated genes. Fluorescence in situ hybridization (FISH) confirmed MYC copy number gain in select cases, and immunohistochemistry to evaluate MYC protein expression. The commonest mutations occurred in TP53 (10/13) and RB1 (7/13). Additional mutations in clinically actionable genes, or mutations with a frequency of at least 25%, included the NF1 (3/12), PMS2 (4/12), ROS1 (3/12), KMT2C (4/12), MNX1 (6/12), NOTCH1 (4/12), PCLO (3/12), and PTPRT (3/12) loci. Low level copy number gain suggestive of amplification of the MYC locus was seen in two cases, and confirmed using FISH. MYC protein expression, as assessed by immunohistochemistry, was present in almost all sebaceous carcinoma cases. Our findings support the concept that alterations in TP53 and RB1 are the commonest alterations in sebaceous carcinoma, and suggest that MYC may contribute to the oncogenesis of these tumors.

Case Report: Analysis of Circulating Tumor Cells in a Triple Negative Spindle-Cell Metaplastic Breast Cancer Patient

Circulating tumor cells (CTCs) are a rare population of cells found in the bloodstream and represent key players in the metastatic cascade. Their analysis has proved to provide further core information concerning the tumor. Herein, we aim at investigating CTCs isolated from a 32-year-old patient diagnosed with triple negative spindle-shaped metaplastic breast cancer (MpBC), a rare tumor poorly responsive to therapies and with a dismal prognosis. The molecular analysis performed on the primary tumor failed to underline effective actionable targets to address the therapeutic strategy. Besides the presence of round-shaped CTCs, cells with a spindle shape were present as well, and through molecular analysis, we confirmed their malignant nature. This aspect was coherent with the primary tumor histology, proving that CTCs are released regardless of their morphology. Copy number aberration (CNA) profiling and variant analysis using next-generation sequencing (NGS) showed that these cells did not harbor the alterations exhibited by the primary tumor (PIK3CA G1049A mutation, MYC copy number gain). However, despite the great heterogeneity observed, the amplification of regions involved in metastasis emerged (8q24.22–8q24.23). Our findings support the investigation of CTCs to identify alterations that could have a role in the metastatic process. To the best of our knowledge, this is the first examination of CTCs in an MpBC patient.