Clinical, histopathological and molecular features of dedifferentiated melanomas: An EORTC Melanoma Group Retrospective Analysis

PURPOSE

Dedifferentiated melanoma (DedM) poses significant diagnostic challenges. We aimed to investigate the clinical, histopathological and molecular features of DedM. Methylation signature (MS) and copy number profiling (CNP) were carried out in a subgroup of cases.

PATIENTS AND METHODS

A retrospective series of 78 DedM tissue samples from 61 patients retrieved from EORTC (European Organisation for Research and Treatment of Cancer) Melanoma Group centres were centrally reviewed. Clinical and histopathological features were retrieved. In a subgroup of patients, genotyping through Infinium Methylation microarray and CNP analysis was carried out.

RESULTS

Most patients (60/61) had a metastatic DedM showing most frequently an unclassified pleomorphic, spindle cell, or small round cell morphology akin to undifferentiated soft tissue sarcoma, rarely associated with heterologous elements. Overall, among 20 successfully analysed tissue samples from 16 patients, we found retained melanoma-like MS in only 7 tissue samples while a non-melanoma-like MS was observed in 13 tissue samples. In two patients from whom multiple specimens were analysed, some of the samples had a preserved cutaneous melanoma MS while other specimens exhibited an epigenetic shift towards a mesenchymal/sarcoma-like profile, matching the histological features. In these two patients, CNP was largely identical across all analysed specimens, in line with their common clonal origin, despite significant modification of their epigenome.

CONCLUSIONS

Our study further highlights that DedM represents a real diagnostic challenge. While MS and genomic CNP may help pathologists to diagnose DedM, we provide proof-of-concept that dedifferentiation in melanoma is frequently associated with epigenetic modifications.

Comprehensive routine diagnostic screening to identify predictive mutations, gene amplifications, and microsatellite instability in FFPE tumor material

Background

Sensitive and reliable molecular diagnostics is needed to guide therapeutic decisions for cancer patients. Although less material becomes available for testing, genetic markers are rapidly expanding. Simultaneous detection of predictive markers, including mutations, gene amplifications and MSI, will save valuable material, time and costs.

Methods

Using a single-molecule molecular inversion probe (smMIP)-based targeted next-generation sequencing (NGS) approach, we developed an NGS panel allowing detection of predictive mutations in 33 genes, gene amplifications of 13 genes and microsatellite instability (MSI) by the evaluation of 55 microsatellite markers. The panel was designed to target all clinically relevant single and multiple nucleotide mutations in routinely available lung cancer, colorectal cancer, melanoma, and gastro-intestinal stromal tumor samples, but is useful for a broader set of tumor types.

Results

The smMIP-based NGS panel was successfully validated and cut-off values were established for reliable gene amplification analysis (i.e. relative coverage ≥3) and MSI detection (≥30% unstable loci). After validation, 728 routine diagnostic tumor samples including a broad range of tumor types were sequenced with sufficient sensitivity (2.4% drop-out), including samples with low DNA input (< 10 ng; 88% successful), low tumor purity (5–10%; 77% successful), and cytological material (90% successful). 75% of these tumor samples showed ≥1 (likely) pathogenic mutation, including targetable mutations (e.g. EGFR, BRAF, MET, ERBB2, KIT, PDGFRA). Amplifications were observed in 5.5% of the samples, comprising clinically relevant amplifications (e.g. MET, ERBB2, FGFR1). 1.5% of the tumor samples were classified as MSI-high, including both MSI-prone and non-MSI-prone tumors.

Conclusions

We developed a comprehensive workflow for predictive analysis of diagnostic tumor samples. The smMIP-based NGS analysis was shown suitable for limited amounts of histological and cytological material. As smMIP technology allows easy adaptation of panels, this approach can comply with the rapidly expanding molecular markers.

Identification of Two Protein-Signaling States Delineating Transcriptionally Heterogeneous Human Medulloblastoma

The brain cancer medulloblastoma consists of different transcriptional subgroups. To characterize medulloblastoma at the phosphoprotein-signaling level, we performed high-throughput peptide phosphorylation profiling on a large cohort of SHH (Sonic Hedgehog), group 3, and group 4 medulloblastomas. We identified two major protein-signaling profiles. One profile was associated with rapid death post-recurrence and resembled MYC-like signaling for which MYC lesions are sufficient but not necessary. The second profile showed enrichment for DNA damage, as well as apoptotic and neuronal signaling. Integrative analysis demonstrated that heterogeneous transcriptional input converges on these protein-signaling profiles: all SHH and a subset of group 3 patients exhibited the MYC-like protein-signaling profile; the majority of the other group 3 subset and group 4 patients displayed the DNA damage/apoptotic/neuronal signaling profile. Functional analysis of enriched pathways highlighted cell-cycle progression and protein synthesis as therapeutic targets for MYC-like medulloblastoma.

Abstract 1398: Modeling of drug-protein interactions to support clinical decision making for therapy-resistant EGFR or ALK-positive non-small cell lung carcinoma

Background Activating mutations in epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) rearrangements are drugable targets in respectively 10% and 4% of advanced non-small cell lung cancer (NSCLC) patients. Different EGFR and ALK inhibitors are available for target-dependent and sometimes independent drug resistance. Mutations in the EGFR or ALK kinase domain are major mechanisms of drug-induced resistance. Prediction of protein-drug interactions using protein modeling of these mutated domains in EGFR and ALK could provide valuable information for the selection of drugs for subsequent treatment. Methods Biopsies from advanced NSCLC patients with an activating EGFR mutation or ALK rearrangement that were taken at therapy resistance were analyzed by targeted panel sequencing. In case of unknown or accumulating mutations in the EGFR and ALK kinase domains, docking poses and binding affinities of drug-protein interactions were determined. The outcome of both calculations were used to create a likelihood ranking of currently available ALK and EGFR inhibitors to bind to specific mutated targets. Follow-up data was available for a limited number of patients who were treated based on this prediction. Results Prediction Protein-drug interactions were modeled for 59 EGFR mutations and 24 ALK mutations that were detected at therapy resistance. Prediction of therapeutic activities for gefitinib, afatinib, dacomitinib, for EGFR mutations, and alectinib, ceritinib, entrectinib and lorlatinib for ALK mutations will be shown. Case example Female (35y), never-smoker, cT1bN2M1c NSCLC with metastases in lymph nodes, liver, bones and asymptomatic brain metastases, ALK translocation-positive without known ALK gatekeeper mutations. Treatment with crizotinib was started, but unacceptable liver enzyme toxicity developed after 6 weeks. Switching therapy to alectinib resulted in a complete metabolic response with absence of brain metastases by MRI. After 9 months the patient progressed with liver, brain and leptomeningeal metastases. Treatment with ceritinib had no effect. A liver biopsy revealed the ALK p.(L1196M) gatekeeper mutation. The case was discussed in the molecular tumor board, because this gatekeeper variant was reported to be sensitive to ceritinib. In contrast, ALK-drug interaction modeling indicated a better binding profile of lorlatinib than ceritinib, not only based in binding affinity but also in the ability of lorlatinib to reproduce the bioactive conformation found in literature. The patient was treated with lorlatinib and recovered in 5 days with a persistent partial response at 2 month follow up and significant clinical benefit. Conclusion Modeling of the protein-drug interactions supports clinical decision making for treatment of NSCLC patients in case of therapy resistance to EGFR and ALK inhibitors.

Citation Format: Juliana F. Vilacha Madeira R Santos, Birgitta I. Hiddinga, Leon C. van Kempen, Arja ter Elst, Lucie B. Hijmering, Thijo J. Hiltermann, Ed Schuuring, Matthew R. Groves, Harry J. Groen, Anthonie J. van der Wekken. Modeling of drug-protein interactions to support clinical decision making for therapy-resistant EGFR or ALK-positive non-small cell lung carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1398.

Abstract 1764: Accurate and reproducible detection of fusions and exon skipping events in NSCLC-derived samples using a comprehensive, targeted RNA-Seq system across multiple laboratories

Introduction: Reliable assessment of cancer-associated RNA markers in lung cancer produced by gene-fusions or exon skipping events by next-generation sequencing requires integrated reagents, protocols, and interpretive software that can harmonize procedures and ensure consistent results across laboratories. We evaluated a comprehensive system for targeted RNA-Seq that includes reagents for nucleic acid quantification, library prep, run controls, and companion bioinformatics software. The reproducibility of this system was evaluated in a multi-phase study design at 5 independent laboratories.

Methods: Total nucleic acid (TNA) was isolated from formalin-fixed, paraffin-embedded (FFPE) residual non-small cell lung cancer (NSCLC) tumor biopsies and cell-lines (RT-112, H596, HCC78). These TNA isolates were used to prepare a set of 30 test samples, including a dilution series to assess assay sensitivity. A non-template control and kit positive control were also included. The sample set was evaluated using the QuantideX® NGS RNA Lung Cancer Kit RUO (Asuragen) and sequenced on the MiSeq® system (Illumina) at Asuragen and 4 independent laboratories. Analyses were conducted using QuantideX® NGS Reporter RUO (Asuragen), a software suite that includes a FASTQ processing pipeline and incorporates pre-analytical QC information into the fusion-caller algorithm and reporting tool.

Results: Laboratories were trained on the assay workflow and companion bioinformatics software in less than two days followed by independent library preparation and sequencing workflows. A total of 266 sample libraries were evaluated from inputs down to &lt;10 ng. A single library was excluded from sequencing due to a failed QC status. Specific targeted fusions (ALK, ROS1, FGFR3) and splice variants (MET exon 14 skipping) were detected in 132 libraries and were concordant at all sites. Designs to detect 3’/5’ expression imbalances reported the presence of gene fusions for ALK and ROS1 in a total of 96 libraries with one aberrant call and one missed call, which occurred in libraries flagged as “at risk” by the interpretive software.

Conclusions: The accuracy of this novel targeted NGS assay for RNA fusions and splice variants in NSCLC was demonstrated in a multi-site laboratory evaluation using clinically-relevant specimens and low inputs of TNA. The ability of the panel to detect both common and rare gene fusion transcripts and exon skipping events within an integrated wet- and dry-bench workflow provides a foundation for the reliable detection of oncogenic RNA fusions and aberrant splicing events that can respond to current and emerging targeted therapies. This study highlighted the ease of implementation and consistent performance that can be achieved in different laboratories when the process from sample-to-report is highly integrated.

Citation Format: Gary J. Latham, Richard Blidner, Brian C. Haynes, Shobha Gokul, Maria L. Aguirre, Stephen Hyter, Ziyan Y. Pessetto, Maria Curtis, Dan Su, Tom Halsey, Victor Weigman, Patrick Hurban, Andrew K. Godwin, Leon C. van Kempen. Accurate and reproducible detection of fusions and exon skipping events in NSCLC-derived samples using a comprehensive, targeted RNA-Seq system across multiple laboratories [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1764. doi:10.1158/1538-7445.AM2017-1764

Abstract 754: Treatment decision-making of rare ERBB2 (HER2) mutations in lung cancer; a role for multidisciplinary molecular tumor boards

Introduction:

Breakthroughs in cancer research have resulted in mutation-specific targeted therapies (precision medicine). Most of these new drugs are only effective in patients with an actionable molecular profile. Thus, predictive molecular testing enables oncologists to select individual patients for the most appropriate (targeted) therapy and to reduce the burden of overtreatment. The number of clinically relevant predictive markers that are routinely analyzed is growing rapidly, resulting in the identification of rare mutations, mutations with unknown relevance and coexistence of two or more mutations in the same sample. Incorporating these into the optimal treatment for the individual patient can be complex.

Methods: A total of 2461 sequential tumor biopsies were analyzed at our institute using targeted next generation sequencing (Ion Torrent platform). 230 of these patients were discussed at a weekly Molecular Tumor Board (MTB) meeting. Cases involved 170 lung and 21 colorectal carcinomas, 24 melanomas, 1 GIST and a range of other malignancies with uncommon and rare mutations. The board is composed of pulmonologists, medical oncologists, pathologists and clinical scientists in molecular pathology. The goal of the MTB is to discuss the biological and clinical relevance of rare mutations or uncommon profiles and to suggest treatment options based on registered, off-label or trial-based drugs presently available in the Netherlands.

Results: In this abstract we report on four patients with an ERBB2 exon 20 mutation and 1 patient with ERBB2 amplification received anti-HER2 treatment after an MTB consensus decision. Two patients with an insertion in exon 20 of ERBB2: (c.2313_2324dup; p.(Y772_A775dup)) received first line therapy with afatinib and showed a partial response and stable disease respectively. One patient with a c.2524G&gt;A; p.(V842I) mutation received afatinib and showed stable disease for 3 months. A patient with another ERBB2 exon 20 insertion (c.2326_2327insTAT:p.(G776delinsVC)) received afatinib but had progressive disease within two months. One patient with an ERBB2 amplification by FISH and high (3+) HER2(ERBB2) expression, showed a partial response to trastuzumab. All patients had stage IV and would without genomic knowledge been treated with chemotherapy.

Conclusion: Lung cancer patients with sporadic ERBB2 mutations might benefit from targeted ERBB2 therapy. For an optimal treatment decision, patients with rare mutations in general, may benefit from discussion in a multidisciplinary molecular tumor board. In the future, both the considerations for targeted therapy as well as treatment response and toxicity should be registered in an open-access database and shared with other national and international Molecular Tumor Board initiatives to allow comparison with traditional treatments.

Citation Format: Arja ter Elst, Nils A. 't Hart, Anthonie J. van der Wekken, Wim Timens, Lucie B. Hijmering-Kappelle, Geke A. Hospers, Hilde Jalving, Elise M. van der Logt, Leon C. van Kempen, Sjoukje F. Oosting, Matthew R. Groves, T Jeroen Hiltermann, Anke van den Berg, Harry J. Groen, Ed Schuuring. Treatment decision-making of rare ERBB2 (HER2) mutations in lung cancer; a role for multidisciplinary molecular tumor boards [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 754. doi:10.1158/1538-7445.AM2017-754

A systematic review of clinical studies on hereditary factors in pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

There is growing evidence that pelvic organ prolapse (POP) is at least partly caused by underlying hereditary risk factors. The aim of our study was to provide a systematic literature review and meta-analysis of clinical studies on family history of POP as a risk factor for POP in individual women.

METHODS

The databases PubMed and Embase were searched. Clinical studies reporting on family history of POP in relation to POP in individual women were included.

RESULTS

Sixteen studies were included, of which eight enabled us to calculate a pooled odds ratio (OR). The pooled OR of POP in case of a positive family history of POP was 2.58 (95 % confidence interval 2.12-3.15).

CONCLUSIONS

Women with POP are substantially more likely to have family members with the same condition compared to women without POP. This strengthens the hypothesis that genetic predisposition plays an important role in the development of POP.

Abstract 4835: Gonosome-linked expression of PPP2R3B in cutaneous melanoma correlates with distant metastasis free survival

Background: A strong adverse male effect for melanoma incidence and survival has been reported. No biological explanation, including hormonal differences, has been identified so far. We hypothesize that this gender difference in incidence and survival involves X-linked tumor suppressor genes and/or oncogenes whose expression is affected by X-chromosome alterations.

Methods: DNA and RNA were extracted from 49 fresh frozen primary melanomas (32 females, 17 males, distant metastasis free survival (DMFS) &lt;3 years or follow up &gt;3 years) and subjected to array-based comparative genomic hybridization. Supervised and unsupervised cluster analyses were performed. X-inactivation was studied by Xist RNA in situ hybridization and androgen receptor methylation-sensitive PCR. The expression of a candidate X-linked gene was analyzed by quantitative PCR and correlated with DMFS in uni- and multivariate analyses.

Results: Supervised cluster analyses revealed distinct DNA signatures associated with clinical and histopathological characteristics. Unsupervised clustering identified three groups of which one was composed of predominantly female patients (10/13) and associated with the worst DMFS. This group was characterized by loss of one X-chromosome in 7 of the 13 patients. Loss of X correlated with poor DMFS of female patients (logrank p=0.009). Intriguingly, the lost X chromosome was systematically the inactivated copy. Among the 17 males, Y-chromosome loss correlated with DMFS (logrank p=0.015). We found that the PPP2R3B gene, located within one of the pseudoautosomal regions and thus not inactivated on the inactive X in females, is lost from the Y in males. PPP2R3B encodes a regulatory subunit of protein phosphatase 2 that may negatively control cell proliferation via targets such as CDC6 or RB. Quantitative analysis of PPP2R3B mRNA expression in an independent sample set of melanomas revealed a strong correlation between decreased levels of PPP2R3B expression and poor DMFS irrespective of gender in multivariate analysis (p=0.0007).

Conclusion: Our analyses reveal a specific pattern of X and Y chromosome losses that are associated with melanoma progression. PPP2R3B is a potential gonosome-linked tumor suppressor gene, whose loss of expression correlates with poor DMFS.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4835. doi:10.1158/1538-7445.AM2011-4835

The dual role of the X-linked FoxP3 gene in human cancers

The FoxP3 (forkhead box P3) gene is an X-linked gene that is submitted to inactivation. It is an essential transcription factor in CD4(+)CD25(+)FoxP3 regulatory T cells, which are therapeutic targets in disseminated cutaneous melanoma. Moreover, FoxP3 is an important tumor suppressor gene in carcinomas and has putative cancer suppressor gene function in cutaneous melanoma as well. Therefore understanding the structure and function of the FoxP3 gene is crucial to gaining insight into the biology of melanoma to better develop immunotherapeutics and future therapeutic strategies.

The biology of melanoma prognostic factors

Cutaneous melanoma still represents a paradox among all solid tumors. It is the cancer for which the best prognostic markers ever identified in solid tumors are available, yet there is very little understanding of their biological significance. This review focuses on recent biological data that shed light on the clinical-biological correlations underlining the 2010 American Joint Committee on Cancer (AJCC) melanoma staging system. A major challenge is to replace outcome clustering based on artificial biomarker breakpoints by a continuous multidimensional prognostic model. Major improvement will come from shared computerized tools that allow the generation of continuous likelihood scores for diagnosis, prognosis, and response prediction. This will lead to the development of platforms which can be used by scientists from different fields to integrate and share high-quality data in the pre-competitive setting and generate new probabilistic causal models.