Arjen H. G. Cleven

Loss of H3K27 tri-methylation is a diagnostic marker for malignant peripheral nerve sheath tumors and an indicator for an inferior survival

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that can show overlapping features with benign neurofibromas as well as high-grade sarcomas. Additional diagnostic markers are needed to aid in this often challenging differential diagnosis. Recently mutations in two critical components of the polycomb repressor 2 (PRC2) complex, SUZ12 and EED, were reported to occur specifically in MPNSTs while such mutations are absent in neurofibromas, both in the setting of neurofibromatosis (NF) and sporadic cases. Furthermore, both SUZ12 and EED mutations in MPNSTs were associated with loss of H3K27 tri-methylation, a downstream target of PRC2. Therefore, we tested whether H3K27me3 immunohistochemistry is useful as a diagnostic and prognostic marker for MPNSTs. We performed H3K27me3 immunohistochemistry in 162 primary MPNSTs, 97 neurofibromas and 341 other tumors using tissue microarray. We observed loss of H3K27me3 in 34% (55/162) of all MPNSTs while expression was retained in all neurofibromas including atypical (n=8) and plexiform subtypes (n=24). Within other tumors we detected loss of H3K27me3 in only 7% (24/341). Surprisingly, 60% (9/15) of synovial sarcomas and 38% (3/8) of fibrosarcomatous dermatofibrosarcoma protuberans (DFSP) showed loss of H3K27 trimethylation. Only 1 out of 44 schwannomas showed loss of H3K27me3 and all 4 perineuriomas showed intact H3K27me3. Furthermore, MPNSTs with loss of H3K27 tri-methylation showed inferior survival compared with MPNSTs with intact H3K27 tri-methylation, which was validated in two independent cohorts. Our results indicate that H3K27me3 immunohistochemistry is useful as a diagnostic marker, in which loss of H3K27me3 favors MPNST above neurofibroma. However, H3K27me3 immunohistochemistry is not suitable to distinguish MPNST from its morphological mimicker synovial sarcoma or fibrosarcomatous DFSP. Since loss of H3K27 tri-methylation was related to poorer survival in MPNST, chromatin modification mediated by this specific histone seems to orchestrate more aggressive tumour biology.

Mutation Analysis of H3F3A and H3F3B as a Diagnostic Tool for Giant Cell Tumor of Bone and Chondroblastoma.

Specific H3F3A driver mutations and IDH2 mutations were recently described in giant cell tumor of bone (GCTB) and H3F3B driver mutations in chondroblastoma; these may be helpful as a diagnostic tool for giant cell–containing tumors of the bone. Using Sanger sequencing, we determined the frequency of H3F3A, H3F3B, IDH1, and IDH2 mutations in GCTBs (n=60), chondroblastomas (n=12), and other giant cell–containing tumors (n=24), including aneurysmal bone cyst, chondromyxoid fibroma, and telangiectatic osteosarcoma. To find an easy applicable marker for H3F3A mutation status, H3K36 trimethylation and ATRX expression were correlated with H3F3A mutations. In total, 69% of all GCTBs harbored an H3F3A (G34W/V) mutation compared with 0% of all other giant cell–containing tumors (P<0.001), whereas 70% of chondroblastomas showed an H3F3B (K36M) mutation compared with 0% of other giant cell–containing tumors (P<0.001). Diffuse H3K36 trimethylation positivity was more often seen in mutated H3F3A GCTBs compared with other giant cell–containing tumors (P=0.005). ATRX protein expression was not correlated with H3F3A mutation status. Hotspot mutations in IDH1 or IDH2 were absent. Our results show that H3F3A and H3F3B mutation analysis appears to be a highly specific, although less sensitive, diagnostic tool for the distinction of GCTB and chondroblastoma from other giant cell–containing tumors. Although H3K36 trimethylation and ATRX immunohistochemistry cannot be used as surrogate markers for H3F3A mutation status, mutations in H3F3A are associated with increased H3K36 trimethylation, suggesting that methylation at this residue may play a role in the etiology of the disease.

Analysis of PD-L1, T-cell infiltrate and HLA expression in chondrosarcoma indicates potential for response to immunotherapy specifically in the dedifferentiated subtype

Therapies targeting the programmed cell death 1 (PD-1) or its ligand (PD-L1) promote antitumor T-cell activity, leading to unprecedented long-lasting tumor responses in some advanced cancers. Because of radiotherapy and chemotherapy resistance, no effective treatments have been defined for advanced chondrosarcomas. We here report an immunohistochemical analysis of PD-L1 expression in a large series of conventional, mesenchymal, clear cell and dedifferentiated chondrosarcomas using tissue microarrays. In the PD-L1-positive tumors, we analyzed the immune microenvironment (T-cell and macrophage infiltration as well as HLA class I expression) using whole sections. PD-L1 expression was absent in conventional (n=119), mesenchymal (n=19) and clear cell (n=20) chondrosarcomas. Forty-one percent (9 of the 22) of dedifferentiated chondrosarcomas displayed PD-L1 positivity. These results were confirmed in an independent cohort using whole tissue sections of dedifferentiated chondrosarcomas in which PD-L1 expression was detected in 52% (11 of the 21) of cases. PD-L1 expression was exclusively found in the dedifferentiated component and expression positively correlated with other immune parameters such as high number of tumor-infiltrating lymphocytes (P=0.014) and positive HLA class I expression (P=0.024) but not with patient overall survival (P=0.22). The presence of PD-L1 expression in association with immune-infiltrating cells and HLA class I expression in nearly 50% of the dedifferentiated chondrosarcomas provides rationale for including these patients in clinical trials with PD-1/PD-L1-targeted therapies.

High-grade sarcoma diagnosis and prognosis: Biomarker discovery by mass spectrometry imaging.

The combination of high heterogeneity, both intratumoral and intertumoral, with their rarity has made diagnosis, prognosis of high‐grade sarcomas difficult. There is an urgent need for more objective molecular biomarkers, to differentiate between the many different subtypes, and to also provide new treatment targets. Mass spectrometry imaging (MSI) has amply demonstrated its ability to identify potential new markers for patient diagnosis, survival, metastasis and response to therapy in cancer research. In this study, we investigated the ability of MALDI‐MSI of proteins to distinguish between high‐grade osteosarcoma (OS), leiomyosarcoma (LMS), myxofibrosarcoma (MFS) and undifferentiated pleomorphic sarcoma (UPS) (Ntotal = 53). We also investigated if there are individual proteins or protein signatures that are statistically associated with patient survival. Twenty diagnostic protein signals were found characteristic for specific tumors (p ≤ 0.05), amongst them acyl‐CoA‐binding protein (m/z 11 162), macrophage migration inhibitory factor (m/z 12 350), thioredoxin (m/z 11 608) and galectin‐1 (m/z 14 633) were assigned. Another nine protein signals were found to be associated with overall survival (p ≤ 0.05), including proteasome activator complex subunit 1 (m/z 9753), indicative for non‐OS patients with poor survival; and two histone H4 variants (m/z 11 314 and 11 355), indicative of poor survival for LMS patients.

High p53 protein expression in therapy-related myeloid neoplasms is associated with adverse karyotype and poor outcome

Identification of p53-positive cells by immunohistochemistry in bone marrow from primary myelodysplastic syndrome patients correlates with the presence of TP53 mutations and poor prognosis. Mutations in the tumor suppressor gene TP53 are more frequent in therapy-related acute myeloid leukemia and myelodysplastic syndrome than in de novo disease, but the role of p53 immunohistochemistry in the therapy-related setting has not been specifically investigated. We studied p53 protein immunoreactivity in bone marrow biopsies of therapy-related myeloid neoplasms and correlated protein expression with TP53 mutation status, clinicopathologic features and outcome. We first studied 32 patients with therapy-related acute myeloid leukemia and 63 patients with therapy-related myelodysplastic syndrome/chronic myelomonocytic leukemia from one institution and then validated our results in a separate group of 32 patients with therapy-related acute myeloid leukemia and 56 patients with therapy-related myelodysplastic syndrome from a different institution. Strong p53 immunostaining in ≥1% of bone marrow cells was highly predictive of a TP53 gene mutation (P<0.0001) and was strongly associated with a high-risk karyotype (P<0.0001). The presence of ≥1% p53 strongly positive cells was associated with poorer overall and disease-specific survival, particularly in the subset of patients treated with stem-cell transplantation. In a multivariable Cox regression model, the presence of ≥1% p53 strongly expressing cells was an independent prognostic marker for overall survival in both cohorts, with hazard ratios of 3.434 (CI: 1.751–6.735, P<0.0001) and 3.156 (CI: 1.502–6.628, P=0.002). Our data indicate that p53 protein expression, evaluated in bone marrow biopsies by a widely available immunohistochemical method, prognostically stratifies patients with therapy-related myeloid neoplasms independent of other risk factors. p53 immunostaining thus represents an easily applicable method to assess risk in therapy-related acute myeloid leukemia/myelodysplastic syndrome patients.

Prognostic Metabolite Biomarkers for Soft Tissue Sarcomas Discovered by Mass Spectrometry Imaging

AbstractMetabolites can be an important read-out of disease. The identification and validation of biomarkers in the cancer metabolome that can stratify high-risk patients is one of the main current research aspects. Mass spectrometry has become the technique of choice for metabolomics studies, and mass spectrometry imaging (MSI) enables their visualization in patient tissues. In this study, we used MSI to identify prognostic metabolite biomarkers in high grade sarcomas; 33 high grade sarcoma patients, comprising osteosarcoma, leiomyosarcoma, myxofibrosarcoma, and undifferentiated pleomorphic sarcoma were analyzed. Metabolite MSI data were obtained from sections of fresh frozen tissue specimens with matrix-assisted laser/desorption ionization (MALDI) MSI in negative polarity using 9-aminoarcridine as matrix. Subsequent annotation of tumor regions by expert pathologists resulted in tumor-specific metabolite signatures, which were then tested for association with patient survival. Metabolite signals with significant clinical value were further validated and identified by high mass resolution Fourier transform ion cyclotron resonance (FTICR) MSI. Three metabolite signals were found to correlate with overall survival (m/z 180.9436 and 241.0118) and metastasis-free survival (m/z 160.8417). FTICR-MSI identified m/z 241.0118 as inositol cyclic phosphate and m/z 160.8417 as carnitine. Graphical Abstractᅟ

Targeting survivin as a potential new treatment for chondrosarcoma of bone

Chondrosarcomas are malignant cartilage-forming bone tumors, which are intrinsically resistant to chemo- and radiotherapy, leaving surgical removal as the only curative treatment option. Therefore, our aim was to identify genes involved in chondrosarcoma cell survival that could serve as a target for therapy. siRNA screening for 51 apoptosis-related genes in JJ012 chondrosarcoma cells identified BIRC5, encoding survivin, as essential for chondrosarcoma survival. Using immunohistochemistry, nuclear as well as cytoplasmic survivin expression was analyzed in 207 chondrosarcomas of different subtypes. Nuclear survivin has been implicated in cell-cycle regulation while cytoplasmic localization is important for its anti-apoptotic function. RT–PCR was performed to determine expression of the most common survivin isoforms. Sensitivity to YM155, a survivin inhibitor currently in phase I/II clinical trial for other tumors, was examined in 10 chondrosarcoma cell lines using viability assay, apoptosis assay and cell-cycle analysis. Survivin expression was found in all chondrosarcoma patient samples. Higher expression of nuclear and cytoplasmic survivin was observed with increasing histological grade in central chondrosarcomas. Inhibition of survivin using YM155 showed that especially TP53 mutant cell lines were sensitive, but no caspase 3/7 or PARP cleavage was observed. Rather, YM155 treatment resulted in a block in S phase in two out of three chondrosarcoma cell lines, indicating that survivin is more involved in cell-cycle regulation than in apoptosis. Thus, survivin is important for chondrosarcoma survival and chondrosarcoma patients might benefit from survivin inhibition using YM155, for which TP53 mutational status can serve as a predictive biomarker.

An experimental guideline for the analysis of histologically heterogeneous tumors by MALDI-TOF mass spectrometry imaging

Mass spectrometry imaging (MSI) has been widely used for the direct molecular assessment of tissue samples and has demonstrated great potential to complement current histopathological methods in cancer research. It is now well established that tissue preparation is key to a successful MSI experiment; for histologically heterogeneous tumor tissues, other parts of the workflow are equally important to the experiments success. To demonstrate these facets here we describe a matrix-assisted laser desorption/ionization MSI biomarker discovery investigation of high-grade, complex karyotype sarcomas, which often have histological overlap and moderate response to chemo-/radio-therapy. Multiple aspects of the workflow had to be optimized, ranging from the tissue preparation and data acquisition protocols, to the post-MSI histological staining method, data quality control, histology-defined data selection, data processing and statistical analysis. Only as a result of developing every step of the biomarker discovery workflow was it possible to identify a panel of protein signatures that could distinguish between different subtypes of sarcomas or could predict patient survival outcome. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

Periosteal chondrosarcoma: a histopathological and molecular analysis of a rare chondrosarcoma subtype

Periosteal chondrosarcoma is a rare, malignant cartilage‐forming neoplasm originating from the periosteal surface of bone. We collected 38 cases from the archives of the Netherlands Committee on Bone Tumours, with the aim of studying histological features and evaluating the involvement of isocitrate dehydrogenase 1 (IDH1), EXT, Wnt/β‐catenin, the pRB pathway (CDK4 and p16), and the TP53 pathway (p53 and MDM2).

Identifying the culprit lesion in tumor induced hypophosphatemia, the solution of a clinical enigma

Tumor-induced osteomalacia is a rare acquired metabolic bone disorder characterized by isolated renal phosphate wasting due to abnormal tumor production of fibroblast growth factor 23. We report the case of a 59 year old woman referred to our department with a long history of progressive diffuse muscle weakness and pain, generalized bone pains and multiple insufficiency fractures of heels, ankles and hips due to a hypophosphatemic osteomalacia. A fibroblast growth factor 23-producing phosphaturic mesenchymal tumor localized in the left quadriceps femoris muscle was identified 7 years after onset of symptoms. Excision of the tumor resulted in normalization of serum phosphate and fibroblast growth factor 23 levels and in complete resolution of the clinical picture with disappearance of all musculoskeletal symptoms. This case illustrates the diagnostic difficulties in establishing a diagnosis tumor-induced osteomalacia and in identifying the responsible tumor. Our case underscores the clinical need to investigate all patients with persistent musculoskeletal symptoms for hypophosphatemia. A systematic approach is of pivotal importance because early recognition and treatment of the metabolic abnormality can prevent deleterious effects of osteomalacia on the skeleton.