Anaplastic lymphoma kinase aberrations correlate with metastatic features in pediatric rhabdomyosarcoma

Multisystem ALK-positive histiocytosis: a multi-case study and literature review

BACKGROUND

Anaplastic lymphoma kinase (ALK)-positive histiocytosis, a novel rare histiocytic proliferation, was first described in 2008; it occurs in early infancy with liver and hematopoietic involvement. The spectrum was subsequently broadened to include localized diseases in older children and young adults. However, its full clinicopathological features and molecular lineage have not been fully elucidated.

RESULTS

Here, we report four cases of multisystem ALK-positive histiocytosis without hematopoietic involvement. Clinically, three patients were adults aged between 32 and 51 years. Two patients', whose main manifestations were intracranial mass and numerous micronodules in the thoracoabdominal cavity organs and skin papules respectively, had a partial response to ALK inhibitors after surgery. One patient presented with mediastinal neoplasm without surgical treatment, and progressive disease occurred after two years of ALK inhibitor therapy. The fourth patient was a 17-month-old male with a large intracranial mass and presented with a poor response to ALK inhibitor and chemoradiotherapy; he died eight months after surgery. Pathologically, the histiocytes were large, with abundant eosinophilic cytoplasm, and mixed with variable numbers of foamy cells and Touton giant cells. Interstitial fibrosis was also observed. Histiocytes were positive for macrophage markers (CD68 and CD163) and ALK. KIF5B-ALK fusions were detected in two cases, EML4-ALK in one, and both DCTN1-ALK and VRK2-ALK fusions were detected in one case.

CONCLUSIONS

We observed that ALK inhibitors present robust and durable responses in adult patients but a poor response in young children with central nervous system involvement. There is no consensus on the optimal treatment regimen and long-term prognosis requires further observation. Moreover, every unusual histiocytic proliferative lesion, especially unresectable and multisystem involvement, should be routinely tested for ALK immunohistochemical staining to identify this rare disease.

Primary pulmonary epithelioid inflammatory myofibroblastic sarcoma: a rare entity and a literature review

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive subtype of inflammatory myofibroblastic tumor (IMT) harboring anaplastic lymphoma kinase (ALK) gene fusions and is associated with high risk of local recurrence and poor prognosis. Herein, we present a young, non-smoking male who presented with complaints of cough and dyspnoea and was found to harbor a large right lower lobe lung mass. Biopsy showed a high-grade epithelioid to rhabdoid tumor with ALK and desmin protein expression. The patient initially received 5 cycles of crizotinib and remained stable for 1 year; however, he then developed multiple bony metastases, for which complete surgical resection was performed. Histopathology confirmed the diagnosis of EIMS, with ALK gene rearrangement demonstrated by fluorescence in situ hybridization. Postoperatively, the patient is asymptomatic with stable metastatic disease on crizotinib and has been started on palliative radiotherapy. EIMS is a very rare subtype of IMT that needs to be included in the differential diagnosis of ALKexpressing lung malignancies in young adults.

Spindle cell/sclerosing rhabdomyosarcoma with DCTN1::ALK fusion: broadening the molecular spectrum with potential therapeutic implications

Spindle cell/sclerosing rbabdomyosarcoma (RMS) is a recently characterized variant of RMS with several distinct molecular subtypes. We describe an example occurring in the tongue of a 10-year-old boy with a novel DCTN1::ALK fusion. The tumor exhibited infiltrative growth and was comprised of fascicles and focally whorls of spindle cells with eosinophilic cytoplasm, in a collagenous or myxoid stroma. Moderate cytologic atypia, mitotic activity (2/10 HPFs), and perineural invasion were identified. The tumor cells expressed actin, desmin, MyoD1, myogenin, and ALK. An in-frame fusion between DCTN1 exon 26 and ALK exon 20 was detected by RNA sequencing, which was confirmed by split reads and supported by FISH studies. The tumor showed an indolent behavior with local recurrence 3 years after excision. This study broadens the molecular spectrum of spindle cell/sclerosing RMS and this molecular aberration may represent a potential therapeutic target for unresectable or disseminated disease.

ALK alterations in salivary gland carcinomas

Salivary gland carcinomas represent a heterogeneous group of poorly characterized head and neck tumors. The purpose of this study was to evaluate ALK gene and protein aberrations in a large, well-characterized cohort of these tumors. A total of 182 salivary gland carcinomas were tested for anaplastic lymphoma kinase (ALK) positivity by immunohistochemistry (IHC) using the cut-off of 10% positive cells. ALK positive tumors were subjected to FISH analysis and followed by hybrid capture–based next generation sequencing (NGS). Of the 182 tumors, 8 were ALK positive by IHC. Further analysis using hybrid capture NGS analysis revealed a novel MYO18A (Exon1-40)-ALK (exon 20-29) gene fusion in one case of intraductal carcinoma. Additional genomic analyses resulted in the detection of inactivating mutations in BRAF and TP53, as well as amplifications of ERBB2 and ALK. ALK rearrangements are a rare entity in salivary gland carcinomas. We identified a potentially targetable novel ALK fusion in an intraductal carcinoma of minor salivary glands.

Signaling pathways in Rhabdomyosarcoma invasion and metastasis

Rhabdomyosarcoma (RMS) is an aggressive childhood mesenchymal tumor with two major molecular and histopathologic subtypes: fusion-positive (FP)RMS, characterized by the PAX3-FOXO1 fusion protein and largely of alveolar histology, and fusion-negative (FN)RMS, the majority of which exhibit embryonal tumor histology. Metastatic disease continues to be associated with poor overall survival despite intensive treatment strategies. Studies on RMS biology have provided some insight into autocrine as well as paracrine signaling pathways that contribute to invasion and metastatic propensity. Such pathways include those driven by the PAX3-FOXO1 fusion oncoprotein in FPRMS and signaling pathways such as IGF/RAS/MEK/ERK, PI3K/AKT/mTOR, cMET, FGFR4, and PDGFR in both FP and FNRMS. In addition, specific cytoskeletal proteins, G protein coupled receptors, Hedgehog, Notch, Wnt, Hippo, and p53 pathways play a role, as do specific microRNA. Paracrine factors, including secreted proteins and RMS-derived exosomes that carry cargo of protein and miRNA, have also recently emerged as potentially important players in RMS biology. This review summarizes the known factors contributing to RMS invasion and metastasis and their implications on identifying targets for treatment and a better understanding of metastatic RMS.

Epithelioid and spindle cell rhabdomyosarcoma with FUS-TFCP2 or EWSR1-TFCP2 fusion: report of two cases

The WHO Classification of Tumors of Soft Tissue and Bone divides rhabdomyosarcoma (RMS) into alveolar, embryonal, pleomorphic, and spindle cell/sclerosing types. Advances in molecular diagnostics have allowed for further refinement of RMS classification including the identification of new subtypes. Very rare RMS with epithelioid and spindle cell morphology, female predominance, marked osseous predilection, ALK expression, EWSR1/FUS-TFCP2 gene fusions, and highly aggressive clinical behavior have recently been recognized with only 23 cases reported in the English language literature. Herein, we report two additional cases with detailed clinicopathologic description and molecular confirmation. In brief, two young women presented each with a primary bone tumor-one with a frontal bone tumor and another with an osseous pelvic tumor. Both tumors showed epithelioid to spindle cell morphology, ALK expression, and EWSR1/FUS-TFCP2 gene fusions. Both patients died of disease less than 17 months from diagnosis despite administration of multiple lines of aggressive treatment. In addition, we review the literature and discuss differential diagnostic and potential treatment considerations.

Epithelioid and spindle cell rhabdomyosarcoma with FUS-TFCP2 or EWSR1-TFCP2 fusion: report of two cases

The WHO Classification of Tumors of Soft Tissue and Bone divides rhabdomyosarcoma (RMS) into alveolar, embryonal, pleomorphic, and spindle cell/sclerosing types. Advances in molecular diagnostics have allowed for further refinement of RMS classification including the identification of new subtypes. Very rare RMS with epithelioid and spindle cell morphology, female predominance, marked osseous predilection, ALK expression, EWSR1/FUS-TFCP2 gene fusions, and highly aggressive clinical behavior have recently been recognized with only 23 cases reported in the English language literature. Herein, we report two additional cases with detailed clinicopathologic description and molecular confirmation. In brief, two young women presented each with a primary bone tumor-one with a frontal bone tumor and another with an osseous pelvic tumor. Both tumors showed epithelioid to spindle cell morphology, ALK expression, and EWSR1/FUS-TFCP2 gene fusions. Both patients died of disease less than 17 months from diagnosis despite administration of multiple lines of aggressive treatment. In addition, we review the literature and discuss differential diagnostic and potential treatment considerations.

Overview of « druggable » alterations by histological subtypes of sarcomas and connective tissue intermediate malignancies

We summarize herein the literature data about molecular targeted therapies in sarcomas and conjunctive tissue intermediate malignancies. For each clinical setting, the level of evidence, the mechanism of action and the target are described. The two major axes include (i) identification of subgroups of tumors with druggable alteration irrespective of the histological diagnosis (e.g. NTRK), and (ii) druggable target of pathway related to the physiopathology of the tumor: denosumab and bone giant cell tumor, imatinib and soft tissue giant cell tumor, mTOR inhibitor and PECOMA.

Expanding the Spectrum of Intraosseous Rhabdomyosarcoma: Correlation Between 2 Distinct Gene Fusions and Phenotype

Primary intraosseous rhabdomyosarcomas (RMSs) are extremely rare. Recently 2 studies reported 4 cases of primary intraosseous RMS with EWSR1/FUS-TFCP2 gene fusions, associated with somewhat conflicting histologic features, ranging from spindle to epithelioid. In this study we sought to further investigate the pathologic and molecular abnormalities of a larger group of intraosseous RMSs by a combined approach using targeted RNA sequencing analysis and fluorescence in situ hybridization (FISH). We identified 7 cases, 3 males and 4 females, all in young adults, age range 20 to 39 years (median, 27 y). Three cases involved the pelvis, 2 involved the femur and 1 each involved the maxilla and the skull. Molecular studies identified recurrent gene fusions in all 7 cases tested, including: a novel MEIS1-NCOA2 fusion in 2 cases, EWSR1-TFCP2 in 3 cases, and FUS-TFCP2 gene fusions in 1 case. One case showed a FUS gene rearrangement, without a TFCP2 gene abnormality by FISH. The MEIS1-NCOA2-positive cases were characterized by a more primitive and fascicular spindle cell appearance, while the EWSR1/FUS rearranged tumors had a hybrid spindle and epithelioid phenotype, with more abundant eosinophilic cytoplasm and mild nuclear pleomorphism. Immunohistochemically, all tumors were positive for desmin and myogenin (focal). In addition, 4 tumors with TFCP2-associated gene fusions also coexpressed ALK and cytokeratin. In conclusion, our results suggest a high incidence of gene fusions in primary RMSs of bone, with 2 molecular subsets emerging, defined by either MEIS1-NCOA2 or EWSR1/FUS-TFCP2 fusions, showing distinct morphology and immunophenotype. Additional studies with larger numbers of cases and longer follow-up data are required to definitively evaluate the biological behavior of these tumors and to establish their relationship to other spindle cell RMS genetic groups.

MiRNAs as Players in Rhabdomyosarcoma Development

Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma of childhood and adolescence, is a rare but aggressive malignancy that originates from immature mesenchymal cells committed to skeletal muscle differentiation. Although RMS is, generally, responsive to the modern multimodal therapeutic approaches, the prognosis of RMS depends on multiple variables and for some patients the outcome remains dismal. Further comprehension of the molecular and cellular biology of RMS would lead to identification of novel therapeutic targets. MicroRNAs (miRNAs) are small non-coding RNAs proved to function as key regulators of skeletal muscle cell fate determination and to play important roles in RMS pathogenesis. The purpose of this review is to better delineate the role of miRNAs as a biomarkers or functional leaders in RMS development, so to possibly elucidate some of RMS molecular mechanisms and potentially therapeutically target them to improve clinical management of pediatric RMS.

OLIG2 is a novel immunohistochemical marker associated with the presence of PAX3/7-FOXO1 translocation in rhabdomyosarcomas

BACKGROUND

The most frequent histological types of rhabdomyosarcoma (RMS) in children are embryonal (ERMS) and alveolar (ARMS) tumours. The majority of ARMS are characterized by the presence of PAX3/7-FOXO1 gene fusion and have a worse prognosis than fusion gene-negative ARMS. However, identification of PAX3/7-FOXO1 fusion status is challenging when using formalin-fixed, paraffin-embedded (FFPE) material. Microarray analyses revealed that high expression of several genes is associated with PAX3/7-FOXO1 fusion status. Therefore, we investigated if immunohistochemical approach may detect surrogate marker genes as indicators of fusion gene-positive RMS.

METHODS

Forty five RMS patients were included in the analysis and immunohistochemistry was applied to FFPE tissues collected at diagnosis. Protein expression of OLIG2, a novel marker in RMS, was investigated using antibody EP112 (Cell Marque). In addition already known two markers were also analyzed: TFAP2B using rabbit anti-TFAP2β antibody (Santa Cruz Biotechnology) and ALK using anti-ALK antibody clone D5F3 #3633 (Cell Signalling). Fluorescence in situ hybridization (FISH) was performed on FFPE sections with FOXO1/PAX3 and/or FOXO1/PAX7 probes (Dual Colour Single Fusion Probe, Zytovision).

RESULTS

Our analysis revealed that all three immunohistochemical markers are associated with the presence of PAX3/7-FOXO1 fusion: TFAP2B (p < 0.00001), OLIG2 (p = 0.0001) and ALK (p = 0.0007). Four ARMS had negative PAX3/7-FOXO1 status and none of them displayed positive reaction with the analysed markers. Positive reaction with OLIG2 (6 tumours) was always associated with the presence of PAX3/7-FOXO1 rearrangement. Two additional OLIG2 positive cases showed inconclusive FISH results, but were positive for TFAP2B and ALK, what suggests that these tumours expressed fusion positive signature.

CONCLUSION

Our results indicate that TFAP2B, ALK and a novel marker OLIG2 may serve as surrogate markers for PAX3/7-FOXO1 status what is especially beneficial in cases where poor quality tumour tissue is not suitable for reliable genetic analyses or shows inconclusive result.

Targeting Anaplastic Lymphoma Kinase (ALK) in Rhabdomyosarcoma (RMS) with the Second-Generation ALK Inhibitor Ceritinib

Background

The receptor tyrosine kinase (RTK) anaplastic lymphoma kinase (ALK) has been implicated in the tumorigenesis of rhabdomyosarcoma (RMS). However, the exact role of ALK in RMS is debatable and remains to be elucidated.

Objective

To determine the in vitro and in vivo effects and mechanism of action of the second-generation ALK inhibitor ceritinib on RMS cell growth.

Methods

Effects of ceritinib on cell proliferation, wound healing, cell cycle, and RTK signaling were determined in alveolar and embryonal rhabdomyosarcoma (ARMS, ERMS). In addition, possible synergistic effects of combined treatment with ceritinib and the Abl/Src family kinase inhibitor dasatinib were determined.

Results

Ceritinib treatment led to decreased cell proliferation, cell cycle arrest, apoptosis, and decreased in vivo tumor growth for the ARMS subtype. ERMS cell lines were less affected and showed no cell cycle arrest or apoptosis. Both subtypes lacked intrinsic ALK phosphorylation, and ceritinib was shown to affect the IGF1R signaling pathway. High levels of phosphorylated Src (Tyr416) were present following ceritinib treatment, making combined treatment with a Src inhibitor a potential treatment option. Combined treatment of ceritinib and dasatinib showed synergistic effects in both ERMS and ARMS cell lines.

Conclusion

This study shows that monotherapy with an ALK inhibitor, such as ceritinib, in RMS, has no effect on ALK signaling. However, the synergistic effects of ceritinib and dasatinib are promising, most probably due to targeting of IGF1R and Src.

Electronic supplementary material

The online version of this article (10.1007/s11523-017-0528-z) contains supplementary material, which is available to authorized users.

PPP2R1A regulated by PAX3/FOXO1 fusion contributes to the acquisition of aggressive behavior in PAX3/FOXO1-positive alveolar rhabdomyosarcoma

To better characterize the oncogenic role of the PAX3-FOXO1 fusion protein in the acquisition of aggressive behavior in ARMS, we employed a proteomic approach using a PAX3-FOXO1 knockdown system in ARMS cell lines. This approach revealed a protein list consisting of 107 consistently upregulated and 114 consistently downregulated proteins that were expected to be regulated by PAX3-FOXO1 fusion protein. Furthermore, we identified 16 upregulated and 17 downregulated critical proteins based on a data-mining analysis. We also evaluated the function of PPP2R1A in ARMS cells. The PPP2R1A expression was upregulated at both the mRNA and protein levels by PAX3-FOXO1 silencing. The silencing of PPP2R1A significantly increased the cell growth of all four ARMS cells, suggesting that PPP2R1A still has a tumor suppressive function in ARMS cells; however, the native expression of PPP2R1A was low in the presence of PAX3-FOXO1. In addition, the activation of PP2A-part of which was encoded by PPP2R1A-by FTY720 treatment in ARMS cell lines inhibited cell growth. On the human phospho-kinase array analysis of 46 specific Ser/Thr or Tyr phosphorylation sites on 39 selected proteins, eNOS, AKT1/2/3, RSK1/2/3 and STAT3 phosphorylation were decreased by FTY-720 treatment. These findings suggest that PPP2R1A is a negatively regulated by PAX3-FOXO1 in ARMS. The activation of PP2A-probably in combination with kinase inhibitors-may represent a therapeutic target in ARMS. We believe that the protein expression profile associated with PAX3-FOXO1 would be valuable for discovering new therapeutic targets in ARMS.

Surgical Interventions for Advanced Parameningeal Rhabdomyosarcoma of Children and Adolescents

Owing to its rarity, rhabdomyosarcoma of the head and neck (HNRMS) has seldom been discussed in the literature. As most of the data is based only on the retrospective experiences of tertiary healthcare centers, there are difficulties in formulating a standard treatment protocol. Moreover, the disease is poorly understood at its pathological, genetic, and molecular levels. For instance, 20% of all histological assessment is inaccurate; even an experienced pathologist can confuse rhabdomyosarcoma (RMS) with neuroblastoma, Ewing’s sarcoma, and lymphoma. RMS can occur sporadically or in association with genetic syndromes associated with predisposition to other cancers such as Li-Fraumeni syndrome and neurofibromatosis type 1 (von Recklinghausen disease). Such associations have a potential role in future gene therapies but are yet to be fully confirmed. Currently, chemotherapies are ineffective in advanced or metastatic disease and there is lack of targeted chemotherapy or biological therapy against RMS. Also, reported uses of chemotherapy for RMS have not produced reasonable responses in all cases. Despite numerous molecular and biological studies during the past three decades, the chemotherapeutic regimen remains unchanged. This vincristine, actinomycin, cyclophosphamide (VAC) regime, described in Kilman, et al. (1973) and Koop, et al. (1963), has achieved limited success in controlling the progression of RMS. Thus, the pathogenesis of RMS remains poorly understood despite extensive modern trials and more than 30 years of studies exploring the chemotherapeutic options. This suggests a need to explore surgical options for managing the disease. Surgery is the single most critical therapy for pediatric HNRMS. However, very few studies have explored the surgical management of pediatric HNRMS and there is no standard surgical protocol. The aim of this review is to explore and address such issues in the hope of maximizing the number of options available for young patients with HNRMS.

Rhabdomyosarcoma cells are susceptible to cell death by LDK378 alone or in combination with sorafenib independently of anaplastic lymphoma kinase status

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase that is often overexpressed in rhabdomyosarcoma (RMS). However, its oncogenic and functional role in RMS remains unclear. Therefore, we investigated the antitumor activity of LDK378 (ceritinib), a new second-generation ALK inhibitor approved for patients with ALK-positive non-small-cell lung cancers. Here, we report that LDK378 reduces cell viability and induces cell death in RMS cell lines at low micromolar IC50 concentrations irrespective of ALK expression levels or phosphorylation status. Compared with Karpas 299 non-Hodgkin's lymphoma cells carrying the NPM-ALK fusion gene, RMS cell lines proved to be far less sensitive to LDK378. The broad-range caspase inhibitor zVAD.fmk significantly protects RMS cells from LDK378-mediated cell death, indicating that LDK378 induces caspase-dependent apoptotic cell death. Before the onset of apoptosis, LDK378 reduces phosphorylation of AKT, S6 ribosomal protein, STAT3 and - to a lesser extent - phosphorylation of ERK, showing that it suppresses key survival pathways. Importantly, we identify a synergistic induction of cell death by combining subtoxic concentrations of LDK378 with the multitargeting kinase inhibitor sorafenib. Calculation of the combination index confirmed that this interaction is synergistic. Also, LDK378 cooperates with sorafenib to significantly reduce colony formation of RMS cells, showing that this combination affects long-term clonogenic growth. In conclusion, LDK378 induces caspase-dependent apoptotic cell death in RMS cells independent of their ALK status and synergizes at subtoxic concentrations with sorafenib to induce cell death. These findings have important implications for the use of LDK378 in RMS.

ALK Protein Expression Is Related to Neuroblastoma Aggressiveness But Is Not Independent Prognostic Factor

PURPOSE

In this study, anaplastic lymphoma kinase (ALK) mutation and amplification, ALK protein expression, loss of the nuclear alpha thalassemia/mental retardation syndrome X-linked (ATRX) protein, and telomerase reverse transcriptase (TERT) protein expressionwere studied to investigate potential correlations between these molecular characteristics and clinical features or outcomes in neuroblastoma.

MATERIALS AND METHODS

Seventy-two patients were enrolled in this study. Polymerase chain reaction amplification and direct sequencing were used for mutation analysis. ALK and MYCN amplifications were detected by fluorescence in situ hybridization. Protein expressionwas evaluated by immunohistochemical (IHC) staining.

RESULTS

ALK mutation was found in only two patients (4.1%); ALK amplification was not detected. ALK positivity, loss of nuclear ATRX protein, TERT positivity by IHC were detected in 40 (55.6%), nine (13.0%), and 42 (59.2%) patients, respectively. The incidence of ALK expression increased in accordance with increasing tumor stage (p=0.001) and risk group (p < 0.001). The relapse rate was significantly higher in ALK⁺ patients compared to that of other patients (47.5% vs. 11.3%, p=0.007). However, there was no significant difference in relapse rate when the survival analysis was confined to the high-risk patients.

CONCLUSION

Although ALK mutation was rare and no amplification was observed, ALK protein expression was found in a significant number of patients and was correlated with advanced stage and high-risk neuroblastoma. ALK protein expression could be considered as a marker related to the aggressive neuroblastoma, but it was not the independent prognostic factor for the outcome.