High Chromosomal Instability Research Articles

Discovery of potent, orally active KIF18A inhibitors targeting CIN-high cancer cells.

e15046 Background: KIF18A is a kinesin assisting chromosome congression and alignment during mitosis. It is nonessential in normal, euploid cell division but essential for a subset of aneuploid cancer cells with high chromosomal instability (CIN-high). KIF18A knockdown in these cells leads to mitotic arrest, cytostasis and cell death. As a result, KIF18A is an attractive anticancer target. Methods: Volastra drug discovery efforts identified and validated KIF18A as a promising target using genetic knockdown and pharmacological inhibition with a tool compound. High-throughput screening identified an ATP-noncompetitive hit that was optimized for potency, selectivity, and pharmacokinetic properties. Breadth of efficacy studies against a panel of cancer cell lines were used to formulate responder hypotheses and aid in patient selection. Mechanistic profiling and cell fate determination upon KIF18A inhibition was used to identify target engagement and clinical response biomarkers. Results: Our lead candidates bind to KIF18A with sub-nM potency and exhibit long (̃2 days) drug-target residence time. They are ATP and microtubule uncompetitive. They are highly selective for KIF18A and have no known off-target effects on related kinesins and in an in vitro safety screen. They are orally bioavailable in preclinical species, well tolerated and demonstrate tumor regression in mouse xenograft models. In contrast to many agents that disrupt the mitotic machinery, KIF18A inhibition does not impact growth of proliferating normal cells. Breadth of efficacy studies performed on a large panel of human cancer cell lines reveal sensitivity to KIF18A inhibitors across multiple tumor types including high-grade serous ovarian, as well as subtypes of breast and lung cancer. Conclusions: Volastra’s research efforts have culminated in the discovery of orally active, highly potent, selective, and efficacious KIF18A inhibitors as development candidates.

Chromosomal instability (CIN) in circulating tumor cells (CTC) predicts for taxane sensitivity in metastatic castration-resistant prostate cancer (mCRPC).

5026 Background: Few clinically validated biomarkers can inform therapy (tx) sequencing in mCRPC. Previously, we credentialed a biomarker of CIN in individual CTCs using phenotypic identification of cells with ≥9 large scale transitions (LSTs) and classification of CIN as high when detected in ≥3 CTC/mL (CIN3+). CIN3+ was associated with shorter radiographic progression survival (rPFS) and overall survival (OS) following taxane (T) or androgen receptor signaling inhibitor (ARSi) tx in mCRPC. Similarly, high CIN defined as ≥1 CTC/mL with ≥9 LSTs (CIN1+) predicts worse rPFS and OS following ARSi. Here, we explored if CIN1+ or CIN3+ predicted differential outcomes in pts on-tx with T or ARSi for mCRPC. Methods: We analyzed 208 banked CTC samples from 173 mCRPC pts collected within 30 days prior to starting a new tx with either T (n=88) or ARSi (n=120) in 2012-2017. CTCs were detected using Epic Sciences platform and CIN defined using the phenotypic classifier (PMID 32816908). Retrospective clinical annotation was completed for OS, defined as time from index tx start date to death, and rPFS, defined as index date to date of new or/and increasing lesion size in on-tx radiology report or death. Associations with rPFS and OS were studied according to samples’ CIN1+ and CIN3+ status. T vs. ARSi comparisons were adjusted using Cox models that incorporated pre-tx covariates, i.e. prior T or ARSi txs, total CTC count, presence of visceral disease, and prognostic lab values. Results: The median (range) follow-up from tx start to date of death or last follow-up was 7 (5-9) years. There were 53/120 (44%) pts starting ARSi that had prior ARSi txs and 41/88 (46%) pts starting taxane that had prior taxane txs. CTCs were detected in 184 (88%) samples, CIN1+ in 73 (35%; 64% pre-T, 36% pre-ARSi), and CIN3+ in 47 (22%; 60% pre-T,40% pre-ARSi). Compared to CIN1+, model results (Table) suggest that CIN3+ predicts a longer rPFS (p<0.01), and possibly OS (p=0.05), with T therapy. Compared to CIN1-, CIN3- also predicts a longer OS with ARSi therapy (p=0.04). Conclusions: CIN3+ CTC may be a more discriminating predictive biomarker than CIN1+ to help guide selection of T or ARSi tx in pts with mCRPC. Adequately powered prospective studies are planned. [Table: see text]

Hypoxia-activated neuropeptide Y/Y5 receptor/RhoA pathway triggers chromosomal instability and bone metastasis in Ewing sarcoma

Adverse prognosis in Ewing sarcoma (ES) is associated with the presence of metastases, particularly in bone, tumor hypoxia and chromosomal instability (CIN). Yet, a mechanistic link between these factors remains unknown. We demonstrate that in ES, tumor hypoxia selectively exacerbates bone metastasis. This process is triggered by hypoxia-induced stimulation of the neuropeptide Y (NPY)/Y5 receptor (Y5R) pathway, which leads to RhoA over-activation and cytokinesis failure. These mitotic defects result in the formation of polyploid ES cells, the progeny of which exhibit high CIN, an ability to invade and colonize bone, and a resistance to chemotherapy. Blocking Y5R in hypoxic ES tumors prevents polyploidization and bone metastasis. Our findings provide evidence for the role of the hypoxia-inducible NPY/Y5R/RhoA axis in promoting genomic changes and subsequent osseous dissemination in ES, and suggest that targeting this pathway may prevent CIN and disease progression in ES and other cancers rich in NPY and Y5R.

Downregulation of B3GNT6 is a predictor of poor outcomes in patients with colorectal cancer

BackgroundThe B3GNT6 protein is a member of the O-GlcNAc transferase (OGT) family and is responsible for the production of the core 3 structure of O-glycans. It is generally expressed in the gastrointestinal (GI) tract; however, its clinical significance in colorectal cancer remains largely unexplored.MethodsWe obtained mRNA transcriptomic sequencing data from 3 gene expression omnibus (GEO) datasets (GSE37182, GSE39582, GSE103512) and The Cancer Genome Atlas (TCGA) to compare the B3GNT6 mRNA levels between colorectal cancer and normal tissues and further evaluate its value as a prognostic marker in colorectal cancer. We further validated this at the protein level in our cohort using immunohistochemical staining of B3GNT6 as well as the Human Protein Atlas online database.ResultsB3GNT6 expression was downregulated in colorectal cancer tissues as compared to that in the normal tissues at both mRNA and protein levels. Downregulation of B3GNT6 expression was found to be associated with poor overall survival in patients with colorectal cancer as per the data in GSE39582 and TCGA databases. Low B3GNT6 mRNA levels were significantly associated with chromosome instability (CIN) and KRAS mutations in patients with colorectal cancer. Gene set enrichment analysis (GSEA) revealed that low B3GNT6 expression levels in colorectal cancer were associated with increased proteasome activity.ConclusionsThe results of this study demonstrate that low expression of B3GNT6 is a potential biomarker for poor outcomes in patients with CRC. Moreover, the low expression of B3GNT6 may indicate more frequent activation of the KRAS/ERK signaling pathway, high CIN, and increased proteasomal activity. These novel findings may prove helpful for molecular diagnosis and provide a new therapeutic target for colorectal cancer.

The STING pathway: Therapeutic vulnerabilities in ovarian cancer.

Ovarian cancer is the leading cause of mortality due to gynecologic malignancy. The majority ofwomen diagnosed with the most common subtype, high-grade serous ovarian carcinoma (HGSC), develop resistance to conventional therapies despite initial response to treatment. HGSC tumors displaying DNA damage repair (DDR) gene deficiency and high chromosomal instability mainly associate with higher cytotoxic immune cell infiltration and expression of genes associated with these immune pathways. Despite the high level of immune infiltration observed, the majority of patients with HGSC have not benefited from immunomodulatory treatments as the mechanistic basis of this infiltration is unclear. This lack of response can be primarily attributed to heterogeneity at the levels of both cancer cell genetic alterations and the tumour immune microenvironment. Strategies to enhance anti-tumour immunity have been investigated in ovarian cancer, of which interferon activating therapies present as an attractive option. Of the several type I interferon (IFN-1) stimulating therapies, exogenously activating the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is emerging as a promising avenue. Herein, we highlight our current understanding of how constitutive and induced cGAS-STING pathway activation influences the ovarian tumour microenvironment. We further elaborate on the links between the genomic alterations prevalent in ovarian tumours and how the resultant immune phenotypes can make them more susceptible to exogenous STING pathway activation and potentiate immune-mediated killing of cancer cells. The therapeutic potential of cGAS-STING pathway activation in ovarian cancer and factors implicating treatment outcomes are discussed, providing a rationale for future combinatorial treatment approaches on the backbone of chemotherapy.

Elevated MACC1 Expression in Colorectal Cancer Is Driven by Chromosomal Instability and Is Associated with Molecular Subtype and Worse Patient Survival.

Simple SummaryElevated expression of Metastasis-Associated in Colon Cancer 1 (MACC1) has been identified as a strong prognostic marker of adverse outcomes for human colorectal (CRC) and other solid cancers. The biological basis of high MACC1 expression and the context of its occurrence are still poorly understood. This study investigated whether chromosomal instability and somatic copy number alterations (SCNA) frequently occurring in CRC contribute to MACC1 dysregulation, with prognostic and predictive impact.Metastasis-Associated in Colon Cancer 1 (MACC1) is a strong prognostic biomarker inducing proliferation, migration, invasiveness, and metastasis of cancer cells. The context of MACC1 dysregulation in cancers is, however, still poorly understood. Here, we investigated whether chromosomal instability and somatic copy number alterations (SCNA) frequently occurring in CRC contribute to MACC1 dysregulation, with prognostic and predictive impacts. Using the Oncotrack and Charité CRC cohorts of CRC patients, we showed that elevated MACC1 mRNA expression was tightly dependent on increased MACC1 gene SCNA and was associated with metastasis and shorter metastasis free survival. Deep analysis of the COAD-READ TCGA cohort revealed elevated MACC1 expression due to SCNA for advanced tumors exhibiting high chromosomal instability (CIN), and predominantly classified as CMS2 and CMS4 transcriptomic subtypes. For that cohort, we validated that elevated MACC1 mRNA expression correlated with reduced disease-free and overall survival. In conclusion, this study gives insights into the context of MACC1 expression in CRC. Increased MACC1 expression is largely driven by CIN, SCNA gains, and molecular subtypes, potentially determining the molecular risk for metastasis that might serve as a basis for patient-tailored treatment decisions.

Prognostic Implications and Immune Infiltration Characteristics of Chromosomal Instability-Related Dysregulated CeRNA in Lung Adenocarcinoma.

An accumulating body of research indicates that long-noncoding RNAs (lncRNAs) regulate the target genes and act as competitive endogenous RNAs (ceRNAs) playing an indispensable role in lung adenocarcinoma (LUAD). LUAD is frequently accompanied by the feature of chromosomal instability (CIN); however, CIN-related ceRNAs have not been investigated yet. We systematically analyzed and integrated CIN-related dysregulated ceRNAs characteristics in LUAD samples for the first time. In TCGA LUAD cohort, CIN in tumor samples was significantly higher than that in those of adjacent, and patients with high CIN risk tended to have worse clinical outcomes. We constructed a double-weighted CIN-related dysregulated ceRNA network, in which edge weight and node weight represented the disorder extent of ceRNA and the correlation of RNA expression level and prognosis, respectively. After module mining and analysis, a potential prognostic biomarker composed of 12 RNAs (8 mRNAs and 4 lncRNAs) named CIN-related dysregulated ceRNAs (CRDC) was obtained. The CRDC risk score had a positive relation with clinical stage and CIN, and patients with high CRDC risk scores exhibited poor prognosis. Moreover, CRDC tended to be an independent risk factor with high robustness to overcome the effect of multicollinearity among other explanatory variables for disease-specific survival (DSS) in TCGA and two GEO cohorts. The result of functional analysis indicated that CRDC was involved in multiple cancer progresses, especially immune-related pathways. The patients with lower CRDC risk had higher B cell, T cell CD4+, T cell CD8+, neutrophil, macrophage, and myeloid dendritic cell infiltration than the patients with higher CRDC risk. Meanwhile, patients with lower CRDC risk could get more benefits from immunological therapy. The results suggested that the CRDC could be a potential prognostic biomarker and an immunotherapy predictor for lung adenocarcinoma.

Characterization of Chromosomal Instability in Glioblastoma.

Glioblastoma multiforme (GBM) is a malignant tumor of the central nervous system (CNS). The poor prognosis of GBM due to resistance to therapy has been associated with high chromosomal instability (CIN). Replication stress is a major cause of CIN that manifests as chromosome rearrangements, fragility, and breaks, including those cytologically expressed within specific chromosome regions named common fragile sites (CFSs). In this work, we characterized the expression of human CFSs in the glioblastoma U-251 MG cell line upon treatment with the inhibitor of DNA polymerase alpha aphidicolin (APH). We observed 52 gaps/breaks located within previously characterized CFSs. We found 17 to be CFSs in GBM cells upon treatment with APH, showing a frequency equal to at least 1% of the total gaps/breaks. We report that two CFSs localized to regions FRA2E (2p13/p12) and FRA2F (2q22) were only found in U-251 MG cells, but not lymphocytes or fibroblasts, after APH treatment. Notably, these glioblastoma-specific CFSs had a relatively high expression compared to the other CFSs with breakage frequency between ∼7 and 9%. Presence of long genes, incomplete replication, and delayed DNA synthesis during mitosis (MiDAS) after APH treatment suggest that an impaired replication process may contribute to this loci-specific fragility in U-251 MG cells. Altogether, our work offers a characterization of common fragile site expression in glioblastoma U-251 MG cells that may be further exploited for cytogenetic and clinical studies to advance our understanding of this incurable cancer.

YES1 and MYC Amplifications as Synergistic Resistance Mechanisms to Different Generation ALK Tyrosine Kinase Inhibitors in Advanced NSCLC: Brief Report of Clinical and Preclinical Proofs

IntroductionALK tyrosine kinase inhibitors (TKIs) are the standard treatment for advanced ALK-positive NSCLC. Nevertheless, drug resistance inevitably occurs. Here, we report a case of a patient with metastatic ALK-positive lung adenocarcinoma with an impressive resistance to sequential treatment with ALK TKIs mediated by YES1 and MYC amplification in a contest of epithelial-to-mesenchymal transition and high progressive chromosomal instability. MethodsThe patient received, after chemotherapy and 7 months of crizotinib, brigatinib and lorlatinib with no clinical benefit to both treatments. A study of resistance mechanisms was performed with whole exome sequencing on different biological samples; primary cell lines were established from pleural effusion after lorlatinib progression. ResultsAt whole exome sequencing analysis, YES1 and MYC amplifications were observed both in the pericardial biopsy and the pleural effusion samples collected at brigatinib and lorlatinib progression, respectively. Increasing chromosomal instability from diagnostic biopsy to pleural effusion was also observed. The addition of dasatinib to brigatinib or lorlatinib restored the sensitivity in primary cell lines; data were confirmed also in H3122_ALK-positive model overexpressing both YES1 and MYC. ConclusionsIn conclusion, YES1 and MYC amplifications are candidates to justify a rapid acquired resistance to crizotinib entailing primary brigatinib and lorlatinib resistance. In this context, a combination strategy of ALK TKI with dasatinib could be effective to overcome a rapid resistance.

Immune subtypes and neoantigen-related immune evasion in advanced colorectal cancer

SummaryElimination of cancerous cells by the immune system is an important mechanism of protection from cancer, however, its effectiveness can be reduced owing to development of resistance and evasion. To understand the systemic immune response in advanced untreated primary colorectal cancer, we analyze immune subtypes and immune evasion via neoantigen-related mechanisms. We identify a distinctive cancer subtype characterized by immune evasion and very poor overall survival. This subtype has less clonal highly expressed neoantigens and high chromosomal instability, resulting in adaptive immune resistance mediated by the immune checkpoint molecules and neoantigen presentation disorders. We also observe that neoantigen depletion caused by immunoediting and high clonal neoantigen load are correlated with a good overall survival. Our results indicate that the status of the tumor microenvironment and neoantigen composition are promising new prognostic biomarkers with potential relevance for treatment plan decisions in advanced CRC.

Evolutionary patterns of chromosomal instability and mismatch repair deficiency in proximal and distal colorectal cancer.

Colorectal carcinomas (CRCs) progress through heterogeneous pathways. The aim of this study was to analyse whether or not the cytogenetic evolution of CRC is linked to tumour site, level of chromosomal imbalance and metastasis. A set of therapy-naïve pT3 CRCs comprising 26 proximal and 49 distal pT3 CRCs was studied by combining immunohistochemistry of mismatch repair (MMR) proteins, microsatellite analyses and molecular karyotyping as well as clinical parameters. A MMR deficient/microsatellite-unstable (dMMR/MSI-H) status was associated with location of the primary tumour proximal to the splenic flexure, and dMMR/MSI-H tumours presented with significantly lower levels of chromosomal imbalances compared with MMR proficient/microsatellite-stable (pMMR/MSS) tumours. Oncogenetic tree modelling suggested two evolutionary clusters characterized by dMMR/MSI-H and chromosomal instability (CIN), respectively, for both proximal and distal CRCs. In CIN cases, +13q, -18q and +20q were predicted as preferentially early events, and -1p, -4 -and -5q as late events. Separate oncogenetic tree models of proximal and distal cases indicated similar early events independent of tumour site. However, in cases with high CIN defined by more than 10 copy number aberrations, loss of 17p occurred earlier in cytogenetic evolution than in cases showing low to moderate CIN. Differences in the oncogenetic trees were observed for CRCs with lymph node and distant metastasis. Loss of 8p was modelled as an early event in node-positive CRC, while +7p and +8q comprised early events in CRC with distant metastasis. CRCs characterized by CIN follow multiple, interconnected genetic pathways in line with the basic 'Vogelgram' concept proposed for the progression of CRC that places the accumulation of genetic changes at centre of tumour evolution. However, the timing of specific genetic events may favour metastatic potential.

Diverse \u2018just-right\u2019 levels of chromosomal instability and their clinical implications in neoadjuvant treated gastric cancer

BackgroundThe Cancer Genome Atlas (TCGA) consortium described EBV positivity(+), high microsatellite instability (MSI-H), genomic stability (GS) and chromosomal instability (CIN) as molecular subtypes in gastric carcinomas (GC). We investigated the predictive and prognostic value of these subtypes with emphasis on CIN in the context of neoadjuvant chemotherapy (CTx) in GC.MethodsTCGA subgroups were determined for 612 resected adenocarcinomas of the stomach and gastro-oesophageal junction (291 without, 321 with CTx) and 143 biopsies before CTx.EBV and MSI-H were analysed by standard assays. CIN was detected by multiplex PCRs analysing 22 microsatellite markers. Besides the TCGA classification, CIN was divided into four CIN-subgroups: low, moderate, substantial, high. Mutation profiling was performed for 52 tumours by next-generation sequencing.ResultsEBV(+) (HR, 0.48; 95% CI, 0.23–1.02), MSI-H (HR, 0.56; 95% CI, 0.35–0.89) and GS (HR, 0.72; 95% CI, 0.45–1.13) were associated with increased survival compared to CIN in the resected tumours. Considering the extended CIN-classification, CIN-substantial was a negative prognostic factor in uni- and multivariable analysis in resected tumours with CTx (each p < 0.05). In biopsies before CTx, CIN-high predicted tumour regression (p = 0.026), but was not prognostically relevant.ConclusionA refined CIN classification reveals tumours with different biological characteristics and potential clinical implications.

Centrosome Aberrations as Drivers of Chromosomal Instability in Breast Cancer.

Chromosomal instability (CIN), or the dynamic change in chromosome number and composition, has been observed in cancer for decades. Recently, this phenomenon has been implicated as facilitating the acquisition of cancer hallmarks and enabling the formation of aggressive disease. Hence, CIN has the potential to serve as a therapeutic target for a wide range of cancers. CIN in cancer often occurs as a result of disrupting key regulators of mitotic fidelity and faithful chromosome segregation. As a consequence of their essential roles in mitosis, dysfunctional centrosomes can induce and maintain CIN. Centrosome defects are common in breast cancer, a heterogeneous disease characterized by high CIN. These defects include amplification, structural defects, and loss of primary cilium nucleation. Recent studies have begun to illuminate the ability of centrosome aberrations to instigate genomic flux in breast cancer cells and the tumor evolution associated with aggressive disease and poor patient outcomes. Here, we review the role of CIN in breast cancer, the processes by which centrosome defects contribute to CIN in this disease, and the emerging therapeutic approaches that are being developed to capitalize upon such aberrations.

Targeting cytokinesis bridge proteins to kill high-CIN type tumors

As a common feature of tumors, chromosomal instability (CIN) not only forces carcinomatous evolution, but also loads cancer cells with extra pressure through a robust imbalance of genome patterning that may be used for cancer treatment. Errors in cytokinesis increase CIN, so cytokinesis components are valuable targets for treating cancer. However, due to the short time span and confined space of cytokinesis bridges, profiling cytokinesis factors is challenging. Taking advantage of engineered ascorbate peroxidase (APEX2), we established a cytokinesis bridge-APEX reaction in living cells. A total of 218 cytokinesis bridge proteins were identified with high reliability. Knockdown of cytokinesis bridge genes generated micronuclei that activate the cGAS-pathway and cause apoptosis in cancer cells bearing high CIN rather than low CIN. Thus, our study proposes a strategy for killing high-CIN tumors regardless of tumor type, and provides a proteome resource of cytokinetic bridges for future research.

Genomic Profiling Reveals the Molecular Landscape of Gastrointestinal Tract Cancers in Chinese Patients.

Gastrointestinal tract cancers have high incidence and mortality in China, but their molecular characteristics have not been fully investigated. We sequenced 432 tumor samples from the colorectum, stomach, pancreas, gallbladder, and biliary tract to investigate cancer-related mutations and detail the landscape of microsatellite instability (MSI), tumor mutation burden (TMB), and chromosomal instability (CIN). We observed the highest TMB in colorectal and gastric cancers and the lowest TMB in gastrointestinal stromal tumors (GISTs). Twenty-four hyper-mutated tumors were identified only in colorectal and gastric cancers, with a significant enrichment of mutations in the polymerase genes (POLE, POLD1, and POLH) and mismatch repair (MMR) genes. Additionally, CIN preferentially occurred in colorectal and gastric cancers, while pancreatic, gallbladder, and biliary duct cancers had a much lower CIN. High CIN was correlated with a higher prevalence of malfunctions in chromosome segregation and cell cycle genes, including the copy number loss of WRN, NAT1, NF2, and BUB1B, and the copy number gain of MYC, ERBB2, EGFR, and CDK6. In addition, TP53 mutations were more abundant in high-CIN tumors, while PIK3CA mutations were more frequent in low-CIN tumors. In colorectal and gastric cancers, tumors with MSI demonstrated much fewer copy number changes than microsatellite stable (MSS) tumors. In colorectal and gastric cancers, the molecular characteristics of tumors revealed the mutational diversity between the different anatomical origins of tumors. This study provides novel insights into the molecular landscape of Chinese gastrointestinal cancers and the genetic differences between tumor locations, which could be useful for future clinical patient stratification and targeted interventions.

Differential whole-genome doubling and homologous recombination deficiencies across breast cancer subtypes from the Taiwanese population

Whole-genome doubling (WGD) is an early macro-evolutionary event in tumorigenesis, involving the doubling of an entire chromosome complement. However, its impact on breast cancer subtypes remains unclear. Here, we performed a comprehensive and quantitative analysis of WGD and its influence on breast cancer subtypes in patients from Taiwan and consequently highlight the genomic association between WGD and homologous recombination deficiency (HRD). A higher manifestation of WGD was reported in triple-negative breast cancer, conferring high chromosomal instability (CIN), while HER2 + tumors exhibited early WGD events, with widely varied CIN levels, compared to luminal-type tumors. An association of higher activity of de novo indel signature 2 with WGD and HRD in Taiwanese breast cancer patients was reported. A control test between WGD and pseudo non-WGD samples was further employed to support this finding. The study provides a better comprehension of tumorigenesis in breast cancer subtypes, thus assisting in personalized treatment.

613P Chromosomal instability (CIN) biomarker in circulating tumor cells (CTC) may predict for therapy resistance in metastatic castration-resistant prostate cancer (mCRPC)

Large scale transitions (LSTs) are chromosomal breakages that generate gains or losses ≥10 Mb. As an indicator of CIN, we previously validated a single-cell phenotypic classifier for identification of CTCs with at least 9 LSTs per cell (pLST-high). High CIN, defined as 3 or more pLST-high CTCs in a sample at baseline, was associated with shorter overall survival. Here, we explored high CIN as a predictive marker of drug sensitivity for patients (pts) with mCRPC.

High chromosome instability identified by low-pass whole-genome sequencing assay is associated with TP53 copy loss and worse prognosis in BRCA1 germline mutation breast cancer

BackgroundThough BRCA1 mutation is the most susceptible factor of breast cancer, its prognostic value is disputable. Here in this study, we use a novel method which based on whole-genome analysis to evaluate the chromosome instability (CIN) value and identified the potential relationship between CIN and prognosis of breast cancer patients with germline-BRCA1 mutation.Materials and methodsSanger sequencing or a 98-gene panel sequencing assay was used to screen for BRCA1 germline small mutations in 1151 breast cancer patients with high-risk factors. MLPA assay was employed to screen BRCA1 large genomic rearrangements in familial breast cancer patients with BRCA1 negative for small mutations. Thirty-two samples with unique BRCA1 germline mutation patterns were further subjected to CIN evaluation by LPWGS (low-pass whole-genome sequencing) technology.ResultsFirstly, 113 patients with germline BRCA1 mutations were screened from the cohort. Further CIN analysis by the LPWGS assay indicated that CIN was independent from the mutation location or type of BRCA1. Patients with high CIN status had shorter disease-free survival rates (DFS) (HR = 6.54, 95% CI 1.30–32.98, P = 0.034). The TP53 copy loss was also characterized by LPWGS assay. The rates of TP53 copy loss in CIN high and CIN low groups were 85.71% (12/14) and 16.67% (3/18), respectively.ConclusionCIN-high is a prognostic factor correlated with shorter DFS and was independent with the germline BRCA1 mutation pattern. Higher CIN values were significantly correlated with TP53 copy loss in breast cancer patients with germline BRCA1 mutation. Our results revealed a reliable molecular parameter for distinguishing patients with poor prognosis from the BRCA1-mutated breast cancer patients.

Genomic Analysis of Response to Neoadjuvant Chemotherapy in Esophageal Adenocarcinoma.

Simple SummaryEsophageal adenocarcinoma (EAC) is a cancer with very poor survival outcomes. Patients are treated with pre-operative chemotherapy or chemoradiotherapy before surgery. However, four out of every five patients do not respond to pre-operative therapy and these patients (non-responders) have significantly worse outcomes. Identifying non-responders prior to therapy would allow alternative treatment pathways to be offered to these patients. In this study, we analyze whole genome sequences of pre-treatment biopsies from 65 patients and find that non-responders display chromosomal instability and increased gene copy number alterations. We report a distinct profile of copy number alterations in non-responders compared to responders, predominantly in genes involved in cell cycle control and RTK/Ras signaling. Mutations in the tumor suppressor NAV3 are also found exclusively in non-responders. These genetic profiles present potential drug targets for investigation in EAC patients who would not respond to pre-operative chemotherapy.Neoadjuvant therapy followed by surgery is the standard of care for locally advanced esophageal adenocarcinoma (EAC). Unfortunately, response to neoadjuvant chemotherapy (NAC) is poor (20–37%), as is the overall survival benefit at five years (9%). The EAC genome is complex and heterogeneous between patients, and it is not yet understood whether specific mutational patterns may result in chemotherapy sensitivity or resistance. To identify associations between genomic events and response to NAC in EAC, a comparative genomic analysis was performed in 65 patients with extensive clinical and pathological annotation using whole-genome sequencing (WGS). We defined response using Mandard Tumor Regression Grade (TRG), with responders classified as TRG1–2 (n = 27) and non-responders classified as TRG4–5 (n =38). We report a higher non-synonymous mutation burden in responders (median 2.08/Mb vs. 1.70/Mb, p = 0.036) and elevated copy number variation in non-responders (282 vs. 136/patient, p < 0.001). We identified copy number variants unique to each group in our cohort, with cell cycle (CDKN2A, CCND1), c-Myc (MYC), RTK/PIK3 (KRAS, EGFR) and gastrointestinal differentiation (GATA6) pathway genes being specifically altered in non-responders. Of note, NAV3 mutations were exclusively present in the non-responder group with a frequency of 22%. Thus, lower mutation burden, higher chromosomal instability and specific copy number alterations are associated with resistance to NAC.

Abstract 2879: MACC1 overexpression in colorectal cancer is driven by chromosomal instability and is associated with molecular subtype

Abstract Metastasis-Associated in Colon Cancer 1 (MACC1) is a strong prognostic marker for human colorectal cancers (CRC). The gene is a key regulator of the HGF/c-Met pathway and its overexpression is associated with cancer cell proliferation, migration, invasiveness and metastasis. The contexture of MACC1 overexpression in cancers is still poorly understood. Here we used the data released by The Cancer Genome Atlas (TCGA) and in silico approaches for a deep and integrative analysis of MACC1 expression modalities in CRCs. First, we curated COAD-READ TCGA datasets and obtained full clinical, genomic, and transcriptomic annotation for a total of 259 CRC samples. In tumors, we showed high heterogeneity of MACC1 mRNA expression levels with data varying from 5.58 to 13.07 U (RNAseq log transformed data - RSEM normalized). By correlating MACC1 expression to clinical data, we showed its levels were associated with anatomic regions of the disease (p=6.35.10-5). The tumors from descending colon and rectum having higher levels than those of the ascending colon and caecum (p=7.44-06). High MACC1 was also associated with higher tumor stages (p=0.01) and nodal invasion (p=0.03). At genomic level, MACC1 mutation was not frequent in CRCs (&amp;lt;2%). The gene is however frequently subjected to gene copy number variation (CNV) due to chromosomal instability and polyploidy (MACC1 CNV values &amp;gt; normal in 155/259: 60%). Correlation analysis indicated strong positive association between MACC1 copy number variations and mRNA expression levels (p&amp;lt;10-16). In an independent dataset, we validate that gain of MACC1 gene copy number and associated higher expression levels correlated with metastasis dissemination and worse outcome of the patients. By analyzing MACC1 with respect of CRC subtypes, we confirmed higher MACC1 levels in MSS tumors with high chromosomal instability (CIN) compared to MSI or genomic stable tumors (GS) (p=1.16-14). Regarding association with CMS1-4 transcriptomic subtypes, the highest expression of MACC1 were observed in CMS2-(epithelial), and CMS4 (mesenchymal) as compared with CMS3 (epithelial with metabolic dysregulation) or CMS1 (MMR deficient). The subset of tumors with very low MACC1 expression were mainly those altered for MLH1 (MSI-H- MMR tumors), notably most of them have normal ploidy. Deconvolution analysis of immune contexture revealed negative correlation between MACC1 expression and immune activation. Stratification using MACC1 as prognostic marker within these tumor types will be evaluated and the gene will also be presented with respect of alterations of key cancer genes in these tumors. Overall, the present study gives insight into the contexture of MACC1 expression in CRC. We showed MACC1 overexpression is largely driven by chromosomal instability and DNA copy number gains. Its expression was dependent on the tumor molecular subtypes. Citation Format: Vincent Vuaroqueaux, Hoor Al-Hasani, Dennis Kobelt, Thomas Risch, Susen Burock, Marie-Laure Yaspo, Heinz-Herbert Fiebig, Ulrike Stein. MACC1 overexpression in colorectal cancer is driven by chromosomal instability and is associated with molecular subtype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2879.