Immunotherapy has revolutionised the treatment of advanced cutaneous squamous cell carcinoma (cSCC). It is important to understand both safety and efficacy in a real-world and trial-ineligible cSCC ...population. We aimed to evaluate safety, efficacy and molecular insights among a broader cSCC population, including immunosuppressed patients, treated with immune checkpoint inhibitors (CPI).
We present a cohort of advanced cSCC patients (n = 61) treated from 2015 to 2020 evaluating the best overall response (BOR) (RECISTv1.1) to CPI therapy, immune-related adverse events (irAEs) and tumour mutational burden (TMB) to correlate with outcomes. A validated geriatric scoring index (CIRS-G) was utilised to assess comorbidities among patients ≥75. These data were compared with published clinical trial results among the broader cSCC population.
BOR to CPI was lower among the entire cohort when compared with trial data (31.5 vs. 48%, P < 0.01), with higher rates of progression (59 vs. 16.5%, P < 0.01), regardless of immunosuppression history or age. Grade 3+ irAEs were more common among responders (P = 0.02), while pre-treatment lymphocyte count and TMB predicted response (P = 0.02).
We demonstrate comparatively lower response rates to CPI among real-world cSCC patients not explained by older age or immunosuppression history alone. Immune-related toxicity, absolute lymphocyte count and TMB predicted CPI response.
BackgroundMerkel cell carcinoma (MCC) is an aggressive neuroendocrine (NE) skin cancer caused by severe UV-induced mutations or expression of Merkel cell polyomavirus (MCPyV) large and small T ...antigens (LT and ST). Despite deep genetic differences between MCPyV-positive and -negative subtypes, current clinical diagnostic markers are indistinguishable, and the expression profile of MCC tumors is, to our knowledge, unexplored.MethodsHere, we leveraged bulk and single-cell RNA-Seq of patient-derived tumor biopsies and cell lines to explore the underlying transcriptional environment of MCC.ResultsStrikingly, MCC samples could be separated into transcriptional subtypes that were independent of MCPyV status. Instead, we observed an inverse correlation between a NE gene signature and the Hippo pathway transcription factors Yes1-associated transcriptional regulator (YAP1) and WW domain-containing transcriptional regulator 1 (WWTR1). This inverse correlation was broadly present at the transcript and protein levels in the tumor biopsies as well as in established and patient-derived cell lines. Mechanistically, expression of YAP1 or WWTR1 in a MCPyV-positive MCC cell line induced cell-cycle arrest at least in part through TEA domain-dependent (TEAD-dependent) transcriptional repression of MCPyV LT.ConclusionThese findings identify what we believe to be a previously unrecognized heterogeneity in NE gene expression within MCC and support a model of YAP1/WWTR1 silencing as essential for the development of MCPyV-positive MCC.FundingUS Public Health Service grants R35CA232128, P01CA203655, and P30CA06516.
Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin caused by either the integration of Merkel cell polyomavirus (MCPyV) and expression of viral T antigens or by ...ultraviolet-induced damage to the tumor genome from excessive sunlight exposure. An increasing number of deep sequencing studies of MCC have identified significant differences between the number and types of point mutations, copy number alterations, and structural variants between virus-positive and virus-negative tumors. However, it has been challenging to reliably distinguish between virus positive and UV damaged MCC.
In this study, we assembled a cohort of 71 MCC patients and performed deep sequencing with OncoPanel, a clinically implemented, next-generation sequencing assay targeting over 400 cancer-associated genes. To improve the accuracy and sensitivity for virus detection compared to traditional PCR and IHC methods, we developed a hybrid capture baitset against the entire MCPyV genome and software to detect integration sites and structure.
Sequencing from this approach revealed distinct integration junctions in the tumor genome and generated assemblies that strongly support a model of microhomology-initiated hybrid, virus-host, circular DNA intermediate that promotes focal amplification of host and viral DNA. Using the clear delineation between virus-positive and virus-negative tumors from this method, we identified recurrent somatic alterations common across MCC and alterations specific to each class of tumor, associated with differences in overall survival. Finally, comparing the molecular and clinical data from these patients revealed a surprising association of immunosuppression with virus-negative MCC and significantly shortened overall survival.
These results demonstrate the value of high-confidence virus detection for identifying molecular mechanisms of UV and viral oncogenesis in MCC. Furthermore, integrating these data with clinical data revealed features that could impact patient outcome and improve our understanding of MCC risk factors.
Cancers avoid immune surveillance through an array of mechanisms, including perturbation of HLA class I antigen presentation. Merkel cell carcinoma (MCC) is an aggressive, HLA-I-low, neuroendocrine ...carcinoma of the skin often caused by the Merkel cell polyomavirus (MCPyV). Through the characterization of 11 newly generated MCC patient-derived cell lines, we identified transcriptional suppression of several class I antigen presentation genes. To systematically identify regulators of HLA-I loss in MCC, we performed parallel, genome-scale, gain- and loss-of-function screens in a patient-derived MCPyV-positive cell line and identified MYCL and the non-canonical Polycomb repressive complex 1.1 (PRC1.1) as HLA-I repressors. We observed physical interaction of MYCL with the MCPyV small T viral antigen, supporting a mechanism of virally mediated HLA-I suppression. We further identify the PRC1.1 component USP7 as a pharmacologic target to restore HLA-I expression in MCC.
Merkel cell polyomavirus is the primary etiological agent of the aggressive skin cancer Merkel cell carcinoma (MCC). Recent studies have revealed that UV radiation is the primary mechanism for ...somatic mutagenesis in nonviral forms of MCC. Here, we analyze the whole transcriptomes and genomes of primary MCC tumors. Our study reveals that virus-associated tumors have minimally altered genomes compared to non-virus-associated tumors, which are dominated by UV-mediated mutations. Although virus-associated tumors contain relatively small mutation burdens, they exhibit a distinct mutation signature with observable transcriptionally biased kataegic events. In addition, viral integration sites overlap focal genome amplifications in virus-associated tumors, suggesting a potential mechanism for these events. Collectively, our studies indicate that Merkel cell polyomavirus is capable of hijacking cellular processes and driving tumorigenesis to the same severity as tens of thousands of somatic genome alterations.
A variety of mutagenic processes that shape the evolution of tumors are critical determinants of disease outcome. Here, we sequenced the entire genome of virus-positive and virus-negative primary Merkel cell carcinomas (MCCs), revealing distinct mutation spectra and corresponding expression profiles. Our studies highlight the strong effect that Merkel cell polyomavirus has on the divergent development of viral MCC compared to the somatic alterations that typically drive nonviral tumorigenesis. A more comprehensive understanding of the distinct mutagenic processes operative in viral and nonviral MCCs has implications for the effective treatment of these tumors.
Merkel Cell Carcinoma Review Xue, Yun; Thakuria, Manisha
Hematology/oncology clinics of North America,
02/2019, Letnik:
33, Številka:
1
Journal Article
Recenzirano
Merkel cell carcinoma is a rare and aggressive cutaneous malignancy of neuroendocrine origin-an often-missed diagnosis due to the wide histopathologic differential diagnosis of malignant small blue ...cell tumors. The advent of electron microscopy and immunohistochemistry staining for cytokeratin 20, a shared neuroendocrine marker, greatly improved diagnostic accuracy. Over the past decade, staging, treatment, and surveillance of the cancer have progressed at a remarkably rapid pace. Herein, the authors provide an update on the current guidelines around diagnosis and management and review the exciting advancements on the horizon.
BackgroundMerkel cell carcinoma is a rare cancer for which the standard-of-care is immune checkpoint blockade in the recurrent/metastatic setting. However, immunotherapy is not effective in all ...patients. A greater understanding of molecular mechanisms and potential predictive biomarkers are unmet needs for clinicians and researchers.MethodsWe undertook a retrospective analysis of 45 patients treated at our institution from 2013 to 2020 to understand the clinical and genomic correlates of clinical benefit from immunotherapy. We gathered data from the electronic health record, including provider notes and results from our institutional next-generation sequencing panel of actionable genomic alterations.ResultsOur cohort predominantly included individuals with stage III disease at diagnosis and stage IV disease at the time of diagnosis of recurrent/metastatic disease. Most patients received immunotherapy in the first line. 43% of patients experienced an objective response to immunotherapy (median duration of response 24.2 months, 95% confidence interval 8.8-not reached) and median overall survival was 15.5 months (95% confidence interval 9.0–28.7) (median follow-up 25.2 months). Lower stage at diagnosis of primary disease and shorter disease-free interval between completion of initial treatment and recurrence were each associated with greater odds of response (odds ratio of 0.06, p=0.04 for stage; odds ratio 0.75, p=0.05 for disease-free interval). The most common single-nucleotide variants among the sequenced cohort were those in TP53 (59%) and RB1 (51%). Single-nucleotide variants in the ARID2 and NTRK1 genes were associated with response without Bonferroni correction (p=0.05), while none of Merkel cell polyomavirus status, total mutational burden, ultraviolet mutational signatures, and copy-number alterations predicted outcomes (figure 1).Abstract 306 Figure 1Mutation landscape by immune checkpoint inhibitor responseMutational plot showing the most frequently mutated genes (top-to-bottom, ≥15%) ordered by response and by total number of SNVs, with gene frequency listed at left (%), and Fisher exact test p values (response versus no response) at right. Asterisks denote values less than 0.05 (significant before Bonferroni correction, for which cutoff for significance is 0.0001 for our panel of 447 genes). The bar graph at top shows the total number of panel single nucleotide variants detected per sample by mutation signature. Blank MCPyV and TMB denote unknown values. MCPyV = Merkel cell polyomavirus status; SNV = single nucleotide variant; TMB = total mutational burden in mutations per Mb.ConclusionsPatients with shorter disease-free interval after definitive treatment may be particularly suitable candidates for immunotherapy. Our molecular findings point to ARID2 and NTRK1 as potential predictive markers and/or therapeutic targets (e.g., with Trk inhibitors), although this association needs to be confirmed in a larger sample.AcknowledgementsAJK receives research funding from the American Society of Hematology and from the Pritzker School of Medicine.Ethics ApprovalThe study was approved by the Dana-Farber institutional review board, protocol numbers 11–104 and 17–000.ConsentWritten informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.
Background:
Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer. Prior to the advent of immunotherapy, treatment options were limited. In our study, we evaluate the impact of tumor cell ...PD-L1 expression and tumor immune microenvironment on survival in MCC patients who were not treated with immune checkpoint inhibitors.
Methods:
Clinical data and tissue samples were collected from 78 patients with confirmed MCC treated at Dana-Farber Cancer Institute. Specimens were analyzed for the distribution of PD-L1 by immunohistochemistry staining (IHC) and standardized analysis. Results were correlated with survival data.
Results:
In this study, membrane and cytoplasmic MCC tumor cell staining for PD-L1 was detected in 22.4% (15 of 67) of cases and PD-L1 staining of intratumoral microvessels and PD-L1 positive immune cells at the infiltrative margins of the tumor in 92.5% (62 of 67) of cases. In patients untreated with immune checkpoint inhibitors, median overall survival was not different for patients based on PD-L1 expression (PD-L1+ 64 months vs. PD-L1- not reached; HR = 1.26, 95% CI: 0.46–3.45;
p
= 0.60).
Conclusion:
PD-L1 expression is frequently detected in MCC tumor cells and tumor microenvironment. PD-L1 expression did not affect prognosis in this cohort that had not received PD-1/L1 blockade.
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