ROS1-GOPC/FIG: a novel gene fusion in hepatic angiosarcoma

Management Strategies and Outcomes in Primary Liver Angiosarcoma

OBJECTIVES

Primary hepatic angiosarcoma is a rare tumor of the liver that originates from endothelial and fibroblastic tissue, with poor prognosis and lack of standardized treatment. We retrospectively analyzed the clinical characteristics and treatment outcomes of 23 patients with primary liver angiosarcoma treated at an academic sarcoma center.

METHODS

We screened all patients with primary liver angiosarcoma treated at Stanford between 2000 and 2022. Data was collected from EPIC electronic medical records and included patient demographics, tumor characteristics, treatment modalities, and patient outcomes. Statistical analysis was completed using Python 3.0, while survival curves were generated using the Kaplan-Meier method and Lifelines Packages.

RESULTS

There were nearly equal numbers of males (11) and females (12) in our study, with most patients aged 70 to 79 at diagnosis. The median overall survival (OS) was 6 months (range 0.07 to 222.6 mo). The 2- and 5-year OS were both 38.6%. 71% of patients received systemic treatment with chemotherapy, while 29% received immunotherapy. Local treatment with surgery or radioembolization was performed in 14% of patients. Three patients in our study displayed particularly improved OS and received various treatments, which ranged from hepatic resection to ipilimumab/nivolumab.

CONCLUSION

Our study demonstrated that primary liver angiosarcoma has poor outcomes despite treatment. Surgical resection with negative margins is the only curative modality. However, most patients present with advanced disease and are not surgical candidates. Further research is needed to identify more effective systemic therapy options for this devastating disease.

A novel TPD52L2-ROS1 gene fusion expanding the molecular alterations in inflammatory myofibroblastic tumor: case report and literature review

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a distinctive tumor composed of spindle cells accompanied by mixed inflammatory cells, and immunohistochemical positivity for ALK (anaplastic lymphoma kinase protein) can be detected in half of IMTs. The diagnosis of ALK-negative IMT could be a challenge. Recently, the fusions of some kinase genes, such as RET, NTRK1, ROS1, etc., are revealed in ALK-negative IMT.

CASE PRESENTATION

A 19-year-old woman presented with swelling of the left upper arm. Magnetic resonance imaging (MRI) scan revealed a tumor in the left postbrachium extended to the left axillary, serratus anterior muscle, and latissimus dorsi muscle. Histopathologically, the irregular-circumscribed tumor was composed of dense spindle-shaped cells with eosinophilic abundant cytoplasm and hyalinized mesenchyme in an inflammatory background. Immunohistochemically (IHC), tumor cells were positive for SMA, MDM2, and p16; the cells were negative for desmin, MyoD1, Myogenin, pan-cytokeratin, S100, SOX10, HMB45, Malen-A, CD34, CD31, CD99, and ALK. By RNA-based NGS, a novel fusion between TPD52L2 3' end of exon 1-4 and ROS1 5' end of exon 36-43 was revealed. ROS1 IHC staining was negative. The final diagnosis of IMT with TPD52L2-ROS1 fusion was made. Subsequently, the patient experienced a good clinical response to Crizotinib, and clinical follow-up showed stable disease after 9 months.

CONCLUSION

This report expands the spectrum of ROS1 gene rearrangements in the IMT and highlights the importance of molecular analysis of IMT for getting a diagnostic clue and determining potential therapeutic strategies.

NVL-520 Is a Selective, TRK-Sparing, and Brain-Penetrant Inhibitor of ROS1 Fusions and Secondary Resistance Mutations

SIGNIFICANCE

The combined preclinical features of NVL-520 that include potent targeting of ROS1 and diverse ROS1 resistance mutations, high selectivity for ROS1 G2032R over TRK, and brain penetration mark the development of a distinct ROS1 TKI with the potential to surpass the limitations of earlier-generation TKIs for ROS1 fusion-positive patients. This article is highlighted in the In This Issue feature, p. 517.

Epithelioid Vascular Lesions: The Differential Diagnosis and Approach in Cytology and Small Biopsies

Vascular neoplasms are rare tumors with a multitude of clinical presentations and behavior, which make accurate identification and subclassification challenging on limited small biopsies. Within the spectrum of these lesions, the ones with epithelioid morphology, such as epithelioid hemangioendothelioma and epithelioid angiosarcoma, are particularly challenging given the morphologic overlap with nonvascular lesions and the limited cells due to hemodilution on sampling. Herein, we review the differential diagnosis of epithelioid vascular neoplasms, with a focus on the cytomorphology, differential diagnoses, and ancillary studies that pathologists should be aware of when evaluating small biopsies and aspirates, including novel translocations, and associated monoclonal immunohistochemistry antibodies, that can help in the diagnosis of some of these tumors. Awareness of these morphologic and ancillary study findings in these rare tumors will hopefully allow pathologists to recognize and render-specific diagnoses on limited samples of these challenging lesions.

The Role of Genomics and Proteomics in Lung Cancer Early Detection and Treatment

Lung cancer is the leading cause of cancer-related death worldwide, with non-small-cell lung cancer (NSCLC) being the primary type. Unfortunately, it is often diagnosed at advanced stages, when therapy leaves patients with a dismal prognosis. Despite the advances in genomics and proteomics in the past decade, leading to progress in developing tools for early diagnosis, targeted therapies have shown promising results; however, the 5-year survival of NSCLC patients is only about 15%. Low-dose computed tomography or chest X-ray are the main types of screening tools. Lung cancer patients without specific, actionable mutations are currently treated with conventional therapies, such as platinum-based chemotherapy; however, resistances and relapses often occur in these patients. More noninvasive, inexpensive, and safer diagnostic methods based on novel biomarkers for NSCLC are of paramount importance. In the current review, we summarize genomic and proteomic biomarkers utilized for the early detection and treatment of NSCLC. We further discuss future opportunities to improve biomarkers for early detection and the effective treatment of NSCLC.

Discovery and functional characterization of the oncogenicity and targetability of a novel NOTCH1-ROS1 gene fusion in pediatric angiosarcoma

Angiosarcomas are rare, malignant soft tissue tumors in children that arise in a wide range of anatomical locations and have limited targeted therapies available. Here, we report a rare case of a pediatric angiosarcoma (pAS) with Li-Fraumeni syndrome (LFS) expressing a novel NOTCH1-ROS1 gene fusion. Although both NOTCH1 and ROS1 are established proto-oncogenes, our study is the first to describe the mechanistic role of NOTCH1-ROS1 fusion arising via intrachromosomal rearrangement. NOTCH1-ROS1 displayed potent neoplastic transformation propensity in vitro, and harbors tumorigenic potential in vivo, where it induced oncogenic activation of the MAPK, PI3K/mTOR, and JAK-STAT signaling pathways in a murine allograft model. We found an unexpected contribution of the NOTCH1 extracellular region in mediating NOTCH1-ROS1 activation and oncogenic function, highlighting the contribution of both NOTCH1 and ROS1 fusion partners in driving tumorigenicity. Interestingly, neither membrane localization nor fusion protein dimerization were found to be essential for NOTCH1-ROS1 fusion oncogenicity. To target NOTCH1-ROS1-driven tumors, we tested both NOTCH1-directed inhibitors and ROS1-targeted tyrosine kinase inhibitors (TKI) in heterologous models (NIH3T3, Ba/F3). Although NOTCH1 inhibitors did not suppress NOTCH1-ROS1-driven oncogenic growth, we found that oral entrectinib treatment effectively suppressed the growth of NOTCH-ROS1-driven tumors. Taken together, we report the first known pAS case with a novel NOTCH1-ROS1 alteration along with a detailed report on the function and therapeutic targeting of NOTCH1-ROS1. Our study highlights the importance of genomic profiling of rare cancers such as pAS to reveal actionable drivers and improve patient outcomes.

Pediatric vascular tumors of the liver: Review from the pathologist’s point of view

Differential diagnosis of pediatric vascular liver tumors can be challenging due to inconsistent nomenclature, histologic overlap and the rarity of some entities. Here we give an up-to-date overview of the most important entities. We discuss the clinic, histology and pathophysiology of hepatic congenital and infantile heman gioma, hepatic epithelioid hemangioendothelioma and hepatic angiosarcoma.

Primary cardiac angiosarcoma directly invading the right lung: An autopsy report

We presented a difficult-to-diagnose case of cardiac angiosarcoma. The patient presented pericardial effusion, but cytology of the effusion was negative. Because cytological detection of angiosarcoma cells is difficult, a possibility of malignancy should not be excluded with negative cytological examination. Biopsy of cardiac mass is the best way for diagnosis.

Primary malignant vascular tumors of the liver in children: Angiosarcoma and epithelioid hemangioendothelioma

Primary malignant vascular neoplasms of the liver, angiosarcoma and epithelioid hemangioendothelioma, are extremely rare entities in the pediatric population. International Society for the Study of Vascular Anomalies classification system is recommended for the pathologic diagnosis of hepatic vascular lesions in this age group. In this article, we highlight the clinicopathologic characteristics of hepatic angiosarcoma and epithelioid hemangioendothelioma in the pediatric population. Hepatic angiosarcoma in children shows a slight female predominance with an average age of 40 mo at diagnosis. The distinct histologic features include whorls of atypical spindled cells and eosinophilic globules, in addition to the general findings of angiosarcoma. Histologic diagnosis of pediatric hepatic angiosarcoma is not always straightforward, and the diagnostic challenges are discussed in the article. Hepatic epithelioid hemangioendothelioma also demonstrates a female predominance, but is more commonly identified in adolescents (median age at diagnosis: 12 years). Histologically, the lesion is characterized by epithelioid cells and occasional intracytoplasmic lumina with a background of fibromyxoid stroma. While WWTR1-CAMTA1 and YAP1-TFE3 fusions have been associated with epithelioid hemangioendothelioma, there are currently no known signature genetic alterations seen in pediatric hepatic angiosarcoma. Advancement in molecular pathology, particularly for pediatric hepatic angiosarcoma, is necessary for a better understanding of the disease biology, diagnosis, and development of targeted therapies.

Identification of a Novel MAN1A1-ROS1 Fusion Gene Through mRNA-based Screening for Tyrosine Kinase Gene Aberrations in a Patient with Leiomyosarcoma

BACKGROUND

Soft tissue sarcomas are a heterogeneous group of rare malignant tumors. Advanced soft tissue sarcomas have a poor prognosis, and effective systemic therapies have not been established. Tyrosine kinases are increasingly being used as therapeutic targets for a variety of cancers and soft tissue sarcomas. Although complex karyotype sarcomas typically tend to carry more potentially actionable genetic alterations than do translocation-associated sarcomas (fusion gene sarcomas), based on our database review, we found that leiomyosarcoma and malignant peripheral nerve sheath tumors have lower frequencies of potential targets than other nontranslocation soft tissue sarcomas. We theorized that both leiomyosarcoma and malignant peripheral nerve sheath tumors might be included in any unique translocations. Furthermore, if tyrosine kinase imbalances, especially fusion genes, occur in patients with leiomyosarcomas and malignant peripheral nerve sheath tumors, tyrosine kinase inhibitors might be a drug development target for this sarcoma. In this study, we used a tyrosine kinase screening system that could detect an imbalance in mRNA between 5'- and 3'-sides in tyrosine kinase genes to identify potential novel therapeutic tyrosine kinase targets for soft tissue sarcomas.

QUESTIONS/PURPOSES

(1) Are there novel therapeutic tyrosine kinase targets in tumors from patients with soft tissue sarcomas that are detectable using mRNA screening focusing on imbalance expressions between the 5' and 3' end of the kinase domain? (2) Can potential targets be verified by RNA sequencing and reverse transcription PCR (RT-PCR)? (3) Will potential fusion gene(s) transform cells in in vitro assays? (4) Will tumors in mice that have an identified fusion gene respond to treatment with a therapeutic drug directed at that target?

METHODS

We used mRNA screening to look for novel tyrosine kinase targets that might be of therapeutic potential. Using functional assays, we verified whether the identified fusion genes would be good therapeutic candidates for soft tissue sarcomas. Additionally, using in vivo assays, we assessed whether suppressing the fusion's kinase activity has therapeutic potential. Study eligibility was based on a patient having high-grade spindle cell and nontranslocation sarcomas, including leiomyosarcoma, malignant peripheral nerve sheath tumor, and high-grade myxofibrosarcoma. Between 2015 and 2019, of the 172 patients with soft tissue sarcomas treated with surgical resection at Juntendo University Hospital, 72 patients had high-grade nontranslocation sarcomas. The analysis was primarily for leiomyosarcoma and malignant peripheral nerve sheath tumors, and there was a limitation of analysis size (reagent limitations) totaling 24 samples at the start of the study. We collected additional samples from a sample bank at the Tokyo Medical and Dental University to increase the number of sarcomas to study. Therefore, in this study, a total of 15 leiomyosarcoma samples, five malignant peripheral nerve sheath tumors samples, and four high-grade myxofibrosarcoma samples were collected to achieve the sample size of 24 patients. To identify tyrosine kinase fusion genes, we designed a NanoString-based assay (NanoString Technologies Inc, Seattle, WA, USA) to query the expression balances regarding transcripts of 90 tyrosine kinases at two points: the 5' end of the kinase domain and within the kinase domain or 3' end of the kinase domain. The tumor's RNA was hybridized to the NanoString probes and analyzed for the expression ratios of outliers from the 3' to 5' end of the kinase domain. Presumed novel fusion events in these positive tumors that were defined by NanoString-based assays were confirmed tyrosine kinase fusion genes by RNA sequencing and confirmatory RT-PCR. Functional analyses consisting of in vitro and in vivo assays were also performed to elucidate whether the identified tyrosine kinase gene fusions were associated with oncogenic abilities and drug responses.

RESULTS

We identified aberrant expression ratios regarding the 3' to 5' end of the kinase domain ratios in ROS1 transcripts in a leiomyosarcoma in a 90-year-old woman. A novel MAN1A1-ROS1 fusion gene was identified from her thigh tumor through RNA sequencing, which was confirmed with real-time PCR. In functional assays, MAN1A1-ROS1 rearrangement revealed strong transforming potential in 3T3 cells. Moreover, in an in vivo assay, crizotinib, a ROS1 inhibitor, markedly inhibited the growth of MAN1A1-ROS1 rearrangement-induced transformed cells in a dose-dependent manner.

CONCLUSION

We conducted tyrosine kinase screening to identify new therapeutic targets in soft tissue sarcomas. We found a novel MAN1A1-ROS1 fusion gene that may be a therapeutic target in patients with leiomyosarcoma. This study demonstrates that the mRNA screening system may aid in the development of useful therapeutic options for soft tissue sarcomas.

CLINICAL RELEVANCE

If novel tyrosine fusions such as MAN1A1-ROS1 fusion can be found in sarcomas from other patients, they could offer avenues for new molecular target therapies for sarcomas that currently do not have effective chemotherapeutic options. Therefore, the establishment of a screening system that includes both genomic and transcript analyses in the clinical setting is needed to verify our discoveries and take the developmental process of treatment to the next step.

GOPC-ROS1 mosaicism in agminated Spitz naevi: report of two cases

Spitz tumors are genetically associated with activating HRAS point mutations or fusions of either ALK, ROS1, NTRK1, NTRK3, RET, MET, MERTK, LCK, BRAF, MAP3K8, or MAP3K3. All these driver gene alterations are mutually exclusive. We report two cases of agminated Spitz naevi with a GOPC-ROS1 fusion. Both cases occurred on the lower limb of young adults. Since adolescence, pigmented or pink-colored papules have been periodically arising in a limited area of skin. In one case, an ill-defined hyperpigmented macule known since childhood was present in the background. Morphologically, at least five lesions were analyzed from each patient. In one case, all were predominantly junctional pigmented Spitz naevi, and in the other case, all were compound unpigmented Spitz naevi. No atypical features were present. RNA-sequencing revealed a GOPC-ROS1 gene translocation in both cases. Split signals of ROS1 gene in fluorescence in situ hybridization were observed not only in the nests of spitzoid melanocytes but also in the bland basal melanocytes surrounding the proliferations. These findings suggest the presence of a GOPC-ROS1 mosaicism in melanocytes with further emergence of agminated Spitz naevi potentially triggered by other genetic alterations. This expands the spectrum of genetic anomalies described in agminated Spitz naevi and our understanding of the mechanisms involved in their emergence.

Hepatic Angiosarcoma: Clinicopathologic Study With an Investigation of ROS1 Gene Rearrangements

BACKGROUND/AIM

Primary hepatic angiosarcoma (PHA) is a rare disease entity with variable morphologic features. Recent findings regarding ROS1 gene rearrangements in PHA may lead to new targeted therapies.

PATIENTS AND METHODS

Thirteen cases (4 resected specimens and 9 biopsy samples) underwent histologic review and morphologic patterns were classified according to a previous study as 1) sinusoidal, 2) peliotic, 3) vasoformative, and 4) solid (epithelioid/spindled). ROS1 immunohistochemistry and investigation of the presence of a ROS1 fusion gene by reverse transcription-polymerase chain reaction were performed in available cases.

RESULTS

Eight of 13 cases (62%) showed vasoformative patterns. Three cases (23%) were classified as sinusoidal and two (15%) as solid patterns. Mortality rate was 90% (9/10) except for three patients lost in follow up. Only one patient is still alive and has survived for 8 months with the disease. All cases tested did not have ROS1 expression (0/9) or a ROS1 fusion gene (0/4).

CONCLUSION

We report 13 cases of PHA with 90% mortality. Vasoformative PHA is the most common histologic type. New findings on ROS1 fusion gene rearrangements could lead to the development of novel targeted therapeutics for PHA patients with dismal prognosis.

Clinical, morphologic, and genomic findings in ROS1 fusion Spitz neoplasms

The presence of a characteristic chimeric fusion as the initiating genomic event is one defining feature of Spitz neoplasms. Characterization of specific subtypes of Spitz neoplasms allows for better recognition facilitating diagnosis. Data on clinical outcomes of the specific tumor types may help in predicting behavior. In this study we present the largest series to date on ROS1 fusion Spitz neoplasms. We present the clinical, morphologic, and genomic features of 17 cases. We compared the morphologic features of these 17 cases to a cohort of 99 other non-ROS1 Spitz neoplasms to assess for features that may have high specificity for ROS1 fusions. These tumors consisted of ten Spitz nevi and seven Spitz tumors. None of the cases met criteria for a diagnosis of Spitz melanoma. Morphologically, the ROS1 fusion tumors of this series were characterized by a plaque-like or nodular silhouette, often densely cellular intraepidermal melanocyte proliferation, frequent pagetosis, tendency toward spindle cell cytomorphology, low grade nuclear atypia, and floating nests with occasional transepidermal elimination. However, there was a significant range in microscopic appearances, including two cases with morphologic features of a desmoplastic Spitz nevus. Different binding partners to ROS1 were identified with PWWP2A and TPM3 being the most common. No case had a recurrence or metastasis. Our findings document that most ROS1 fusion Spitz neoplasms have some typical characteristic microscopic features, while a small proportion will have features overlapping with other genomic subtypes of Spitz neoplasms. Preliminary evidence suggests that they tend to be indolent or low grade neoplasms.

New insights into the pathophysiology and clinical care of rare primary liver cancers

Hepatocholangiocarcinoma, fibrolamellar carcinoma, hepatic haemangioendothelioma and hepatic angiosarcoma represent less than 5% of primary liver cancers. Fibrolamellar carcinoma and hepatic haemangioendothelioma are driven by unique somatic genetic alterations (DNAJB1-PRKCA and CAMTA1-WWTR1 fusions, respectively), while the pathogenesis of hepatocholangiocarcinoma remains more complex, as suggested by its histological diversity. Histology is the gold standard for diagnosis, which remains challenging even in an expert centre because of the low incidences of these liver cancers. Resection, when feasible, is the cornerstone of treatment, together with liver transplantation for hepatic haemangioendothelioma. The role of locoregional therapies and systemic treatments remains poorly studied. In this review, we aim to describe the recent advances in terms of diagnosis and clinical management of these rare primary liver cancers.

Angiosarcomas: histology, immunohistochemistry and molecular insights with implications for differential diagnosis

Angiosarcomas (AS) represent a heterogenous group of tumors with variable clinical presentation. AS share an important morphologic and immunohistochemical overlap with other sarcomas, hence the differential diagnosis is challenging, especially in poorly-differentiated tumors. Although molecular studies provide significant clues, especially in the differential diagnosis with other vascular neoplasms, a thorough hematoxylin and eosin analysis remains an essential tool in AS diagnosis. In this review, we discuss pathological and molecular insights with emphasis on implications for differential diagnosis in cutaneous, breast, soft tissue and visceral AS.

A Catalog of 5' Fusion Partners in ROS1-Positive NSCLC Circa 2020

ROS1 fusion-positive (ROS1+) NSCLC was discovered in 2007, the same year as the discovery of ALK-positive (ALK+) NSCLC but has trailed ALK+ NSCLC in terms of development. There seems to be a differential response to ROS1 inhibitors, which depend on fusion partners (CD74, SLC34A2, or SDC4); thus, knowledge of the fusion partners in ROS1+ NSCLC is important. To date (end of February 2020), we have identified 24 unique 5' fusion partners of ROS1 in ROS1+ NSCLC from published literature and congress proceedings. Thus, we published this catalog for easy reference.