Role of the Hippo-YAP/TAZ Pathway in Epithelioid Hemangioendothelioma and its Potential as a Therapeutic Target.

Epithelioid hemangioendothelioma (EHE) is a rare malignant vascular tumor arising from vascular endothelial cells. This study delves into the molecular mechanisms underlying EHE, with a specific focus on the Hippo-YAP/TAZ pathway. EHE is characterized molecularly by transcriptional co-activator with a PDZ-motif (TAZ)-calmodulin binding transcription activator 1 (CAMTA1) or Yes-associated protein (YAP)-transcription factor E3 (TFE3) fusions. YAP/TAZ, a transcription co-activator, binds to transcription factors and regulates gene expression. The YAP/TAZ and its upstream Hippo pathway are involved in cell proliferation and cell contact inhibition, regulating organ size and carcinogenesis. In addition to oncogenic effects, dysfunction or gene duplication of the Hippo pathway results in a poor prognosis due to epithelial-mesenchymal transformation of epithelial cells, stem cell transformation, and increased drug resistance. Notably, the TAZ-CAMTA1 fusion is specific to EHE, and genetic alterations in the Hippo pathway other than this fusion gene are absent in EHE. The TAZ-CAMTA1 fusion is a promising therapeutic target. This review summarizes recent advances in EHE, focusing on the role of the Hippo-YAP/TAZ pathway in EHE and its potential as a therapeutic target for drug development.

Epithelioid hemangioendothelioma on PET/CT scan.

BACKGROUND: At present, lung cancer ranks among the most frequent malignant diseases. However, according to literature data, mesenchymal lung tumors are very rare, representing less than 0.5% of all malignant lung tumours. Epithelioid hemangioendothelioma of the lungs belongs to this group of uncommon entities. CASE REPORT: We present a case of a 45-year-old male with a history of increasing dyspnoea and abdominal and back pains, developing over the past several months. Vertebral lesions were found on imaging studies. PET/ CT following 18F-fluorodeoxyglucose administration (FDG) showed a large FDG-positive malignant infiltration affecting the thorax, abdominal cavity, and bones. The extension and other characteristics of the mass on PET/ CT did not correspond to any of the common oncologic diseases. With its spread in a plaque-like form predominantly in the right hemithorax and on the surface of the liver, the disease closely resembled malignant mesothelioma. The primary tumour origin could not be clearly identified on PET/ CT scans but they allowed us to choose a suitable site to obtain tissue for pathologic examination. Based on a CT-guided bone bio-psy of the 7th right rib, the dia-gnosis was concluded as epithelioid hemangioendothelioma. Despite an early initiation of systemic treatment, the patient succumbed to the disease only 15 days after the dia-gnosis, due to superior vena cava syndrome and progressive pleural effusion leading to respiratory insufficiency. CONCLUSIONS: Given the extremely low prevalence of epithelioid hemangioendothelioma and its heterogeneous manifestation, it is impossible to base the dia-gnosis solely on disease symptoms, laboratory findings, and imaging modalities. In this respect, pathologic examination has a crucial role. For the same reason, there is a lack of recommendations for the standard-of-care systemic therapy of metastatic disease.

Loss of expression of YAP1 C-terminus as an ancillary marker for epithelioid hemangioendothelioma variant with YAP1-TFE3 fusion and other YAP1-related vascular neoplasms.

Epithelioid hemangioendothelioma (EHE) with YAP1-TFE3 fusion is a recently characterized distinctive variant of EHE that accounts for a small subset (<5%) of cases. It is composed of nests of epithelioid cells with voluminous pale cytoplasm and often shows focally vasoformative architecture. TFE3 immunohistochemistry (IHC) can be used to support the diagnosis; however, studies have questioned its specificity. Yes-associated protein 1 (YAP1), part of the Hippo signaling pathway, is expressed in normal endothelial cells, but becomes disrupted in EHE variant with YAP1-TFE3, such that only a small N-terminal region of YAP1 is expressed in the fusion protein. A recent study also reported YAP1 rearrangements in a subset of retiform and composite hemangioendotheliomas (RHE and CHE). In this study, we evaluated the diagnostic utility of an antibody directed against the C-terminus of YAP1 (YAP1-CT) for EHE with YAP1-TFE3, RHE, and CHE. In total, 78 tumors were included in the study: EHE variant with YAP1-TFE3 (n = 13), conventional (CAMTA1-positive) EHE (n = 20), pseudomyogenic hemangioendothelioma (n = 10), epithelioid hemangioma (n = 19), epithelioid angiosarcoma (n = 10), RHE (n = 4), and CHE (n = 2). IHC was performed using a rabbit monoclonal anti-YAP1 C-terminus antibody. EHE variant showed complete loss of YAP1-CT expression in 10 of 13 (77%) cases. All cases of RHE and CHE, with previously confirmed YAP1 rearrangements, also showed loss of YAP1-CT expression. Loss of YAP1-CT was seen in one conventional EHE (1/20; 5%). All other epithelioid vascular tumors showed retained YAP1-CT expression. Loss of expression of YAP1-CT appears to be associated with good sensitivity and specificity for EHE variant with YAP1-TFE3 fusion and may provide additional support along with TFE3 and CAMTA1 IHC in challenging cases. This marker may also be useful in the diagnosis of RHE and CHE.

TAZ-CAMTA1 and YAP-TFE3 alter the TAZ/YAP transcriptome by recruiting the ATAC histone acetyltransferase complex.

Epithelioid hemangioendothelioma (EHE) is a vascular sarcoma that metastasizes early in its clinical course and lacks an effective medical therapy. The TAZ-CAMTA1 and YAP-TFE3 fusion proteins are chimeric transcription factors and initiating oncogenic drivers of EHE. A combined proteomic/genetic screen in human cell lines identified YEATS2 and ZZZ3, components of the Ada2a-containing histone acetyltransferase (ATAC) complex, as key interactors of both fusion proteins despite the dissimilarity of the C terminal fusion partners CAMTA1 and TFE3. Integrative next-generation sequencing approaches in human and murine cell lines showed that the fusion proteins drive a unique transcriptome by simultaneously hyperactivating a TEAD-based transcriptional program and modulating the chromatin environment via interaction with the ATAC complex. Interaction of the ATAC complex with both fusion proteins indicates that it is a key oncogenic driver and unifying enzymatic therapeutic target for this sarcoma. This study presents an approach to mechanistically dissect how chimeric transcription factors drive the formation of human cancers.

The proliferation of human cells is tightly regulated to ensure that enough cells are made to build and repair organs and tissues, while at the same time stopping cells from dividing uncontrollably and damaging the body. To get the right balance, cells rely on physical and chemical cues from their environment that trigger the biochemical signals that regulate two proteins called TAZ and YAP. These proteins control gene activity by regulating the rate at which genes are copied to produce proteins. If this process becomes dysregulated, cells can grow uncontrollably, causing cancer. In cancer cells, it is common to find TAZ and YAP fused to other proteins. In epithelioid hemangioendothelioma, a rare cancer that grows in the blood vessels, cancerous growth can be driven by a version of TAZ fused to the protein CAMTA1, or a version of YAP fused to the protein TFE3. While the role of TAZ and YAP in promoting gene activity is known, it is unclear how CAMTA1 and TFE3 contribute to cell growth becoming dysregulated. Merritt, Garcia et al. studied sarcoma cell lines to show that these two fusion proteins, TAZ-CAMTA1 and YAP-TFE3, change the pattern of gene activity seen in the cells compared to TAZ or YAP alone. An analysis of molecules that interact with the two fusion proteins identified a complex called ATAC as the cause of these changes. This complex adds chemical markers to DNA-packaging proteins, which control which genes are available for activation. The fusion proteins combine the ability of TAZ and YAP to control gene activity and the ability of CAMTA1 and TFE3 to make DNA more accessible, allowing the fusion proteins to drive uncontrolled cancerous growth. Similar TAZ and YAP fusion proteins have been found in other cancers, which can activate genes and potentially alter DNA packaging. Targeting drug development efforts at the proteins that complex with TAZ and YAP fusion proteins may lead to new therapies.

Aberrant keratin expression is common in primary hepatic malignant vascular tumors: A potential diagnostic pitfall.

Malignant vascular neoplasms such as epithelioid hemangioendothelioma (EHE) and angiosarcoma (AS) can arise within the liver. The aim of this study was to study the expression of keratins CK7, AE1/AE3 and OSCAR in primary hepatic EHE and AS. 9 cases of hepatic EHE and 13 cases of hepatic AS were stained with ERG, CK7, keratin AE1/AE3 and keratin OSCAR. Their expression was graded as 1+ (1-25% of tumor cells positive), 2+ (26-50%), 3+ (51-75%) or 4+ (>75%). ERG was positive in all 9 (100%) EHEs and all 13 (100%) ASs. CK7 was positive in 5/9 (56%) EHEs (2, 1+; 1, 2+; 1, 3+; 1, 4+) and 1/13 (8%) AS (2+). Keratin OSCAR was positive in 6/9 (67%) EHEs (5, 1+; 1, 2+) and 4/13 (31%) ASs (2, 1+; 1, 2+; 1, 4+). Keratin AE1/AE3 was positive in 6/9 (67%) EHEs (3, 1+; 3; 2+) and 4/13 (31%) ASs (2, 1+; 1, 2+; 1, 4+). Overall, 6/ 9 (67%) EHEs were positive for at least one keratin marker, of which 5 were positive for all 3 keratins (AE1/AE3, OSCAR and CK7) while 1 was positive only for 2 keratins (OSCAR and AE1/AE3). 4/13 (31%) of ASs were positive for both keratins OSCAR and AE1/AE3, of which 1 case was also positive for CK7. Aberrant keratin expression is common in primary hepatic EHEs (67%) and ASs (31%). Awareness of this diagnostic pitfall is important for avoiding misdiagnosis of these primary hepatic malignant vascular tumors as carcinomas.

VEGF-VEGFR pathway seems to be the best target in hepatic epithelioid hemangioendothelioma: A case series with review of the literature.

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor originating from endothelial cells. Clinical aspect of the disease covers a wide spectrum from a low-grade tumor to a fatal cancer. Most common sites of EHE are reported as lung, liver and bone. Hepatic EHE (HEHE) is a clinical form with an incidence of less than 1 person in a million. Due to rarity of the disease, there is no standard therapy established. Surgery and liver transplantation still seem to be the best approach if possible. However, most of the patients present with unresectable or metastatic disease. Many conventional chemotherapeutic agents and antiangiogenic drugs have been reported previously in the literature with inconsistent outcomes. Here we report 4 cases of HEHE, who benefit distinctly from anti-VEGF treatments in different settings. While combination of paclitaxel and bevacizumab resulted in partial response in 3 patients, one of them also achieved long-term disease stabilization with bevacizumab maintenance with no adverse event. Two of the patients had clear benefit from pazopanib during the course of disease. One patient was treated with thalidomide for 18 months with stable disease, and is still being followed without any treatment. Although targeting VEGF-VEGFR pathway seems to be the best approach in HEHE, randomized studies are urgently needed to support these findings.

Molecular characterization of hepatic epithelioid hemangioendothelioma reveals alterations in various genes involved in DNA repair, epigenetic regulation, signaling pathways, and cell cycle control.

Epithelioid hemangioendotheliomas (EHE) of the liver are rare, low-malignant vascular tumors whose molecular pathogenesis is incompletely understood. The diagnosis of EHE is challenging, and the course of the disease can be highly variable. Therapeutic options for EHE are limited, including resection of primary and metastatic tumors, organ transplantation and rather ineffective systemic approaches. Driver mutations have been reported (fusion transcripts of either YAP-TFE3 or WWTR1-CAMTA1) but comprehensive molecular profiling has not been performed. Our aim was to molecularly characterize hepatic EHE to identify new molecular targets. Eight primary hepatic EHE were analyzed by next-generation sequencing using a 409-gene panel. The majority of primary hepatic EHE revealed a low number of mutations. Genes that were mutated primarily are involved in DNA repair, epigenetic regulation, signaling pathways and cell cycle control, indicating that EHE present with mutations in various functions. Although only detecting a low mutation rate, a comparison with comprehensive databases (target db V3) revealed mutations in five genes with putative therapeutical options. Therefore, our findings help to shed light on the molecular background of EHE and might pave the way to new therapeutic approaches.

Bisphosphonates as a therapeutic choice for multifocal epithelioid hemangioma of bone: A case report.

RATIONALE: Epithelioid hemangioma (EH) of bone is an intermediate vascular tumor that can be locally aggressive. The optimum management of multifocal EH of bone is not well delineated. We described our experience treating one patient with multifocal EH of bone in an effort to document the effect of bisphosphonates in bone EH. PATIENT CONCERNS: In this report, a 53-year old male patient presented with back pain which was initially been diagnosed of multiple bone metastatic carcinoma by 18F-FDG PET/CT scan and bone scintigraphy. DIAGNOSIS: CT-guided bone biopsy of ilium indicated that puncture tissue had irregular hyperplasia of thick and thin-walled blood vessels, immunohistochemistry revealed positive staining for CD31 and CD34, negative for CAMTA-1, PCK and EMA, which confirmed the diagnosis of multiple EH. INTERVENTIONS: The patient was treated with 4 times of intravenous Zometa (zoledronate, 4 mg each time) with average three-month interval. Bone metabolic markers including serum bone specific alkaline phosphatase (BALP) and type I collagen cross-linked C-terminal telopeptide (CTX) levels were closely monitored before and after use of bisphosphonates each time. OUTCOME: BALP and CTX were significantly lowered following intravenous Zometa and the back pain improved with integrated therapy including bone graft fusion internal fixation surgery and vertebroplasty. CONCLUSIONS: EH of multiple bones responded favorably to intravenous Zometa with improvement of bone metabolic markers. After 1 year on follow-up, the patient was doing well with no significant pain. We suggest that bisphosphonates should be considered in the treatment of multifocal osteolytic EH of bone.

FDG PET/CT of Mediastinal Epithelioid Hemangioendothelioma.

Epithelioid hemangioendothelioma is a rare low- to intermediate-grade malignant vascular neoplasm with a variable clinical course and currently no standardized treatment. We present a case of a 65-year-old woman diagnosed as having mediastinal epithelioid hemangioendothelioma, a location which is very exceptional. FDG PET/CT was more sensitive than CT for staging, revealing intense FDG uptake in the primary tumor and in the metastatic disease. Despite high FDG uptake, the disease was stable with no further specific treatment. Only few reports utilizing FDG PET/CT are available; review of the literature on this subject is included.

Pleura revisited: From histology and pathophysiology to pathology and molecular biology.

Pleural cavity has an interesting physiology that when impaired gives rise to pleural effusions a rather frequent problem in respiratory medicine practice. Their aetiology varies widely producing distinct pathological lesions with different prognosis and treatment. The basic morphological features of pleural diseases, neoplastic and non-neoplastic, will be analysed in this review with an emphasis to their pathophysiology, differential diagnosis and clinicopathological correlations.

Effectiveness of Vascular Markers (Immunohistochemical Stains) in Soft Tissue Sarcomas.

OBJECTIVE: To ascertain the effectiveness of IHC markers of vascular origin like CD31, CD34, FLI1 and ERG in vascular soft tissue sarcomas including angiosarcomas, Kaposi sarcomas, epithelioid hemangioendothelioma and a non-vascular soft tissue sarcoma (Epithelioid sarcoma). STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, from 2011 to 2017. METHODOLOGY: Diagnosed cases of angiosarcomas (n=48), epithelioid hemangioendothelioma (n=9), Kaposi sarcoma (n=9) and epithelioid sarcoma (n=20) were selected. Immunohistochemical staining as performed on formalin fixed paraffin embedded sections. The sections were stained for the following markers: CD34 (VENTANA clone Q Bend 10), CD31 (Leica clone 1 A 10), FLI1 (CELL MARQUE clone MRQ-1) and ERG (CELL MARQUE clone EP111). RESULTS: A complete panel of CD34, CD31 and ERG was applied on 8/48 cases of angiosarcomas with triple positivity in 6 cases. Eight cases showed positivity for only CD31 and ERG and 2 cases showed positivity for only ERG. A complete panel of CD34, CD31 and ERG was applied on 3/9 cases of epithelioid hemangioendothelioma with positivity for all markers in 2 cases. Combined positivity for ERG and CD34 was seen in 2 cases and on 4 cases only CD31 immunohistochemical was solely applied with 100% positivity. FLI1 was not applied on any case. Among 9 cases of Kaposi sarcoma, ERG, CD34 and CD31 in combination were applied on only 1 case with triple positivity. Remaining cases show positivity for either CD34, CD31 or FLI1. Majority of cases of epithelioid sarcomas were diagnosed on the basis of cytokeratin and CD34 positivity with loss of INI1. The other vascular markers showed negativity in all cases. CONCLUSION: Among these four markers, ERG immunohistochemical stain is highly effective for endothelial differentiation due to its specific nuclear staining pattern in normal blood vessel endothelial cells (internal control) as well as neoplastic cells of vascular tumors and lack of background staining.

Telatinib Is an Effective Targeted Therapy for Pseudomyogenic Hemangioendothelioma.

Purpose: Pseudomyogenic hemangioendothelioma (PHE) is an extremely rare locally aggressive neoplasm with endothelial differentiation, which often presents with multiple lesions. These tumors have characteristic SERPINE1-FOSB fusions. We report a 17 years old patient with advanced unresectable PHE with a durable complete remission to the multi-tyrosine kinase inhibitor telatinib. The aim of this study was to generate an in vitro model for PHE, to study the functional consequences of SERPINE1-FOSB in endothelial cells, and its interaction with telatinib, to biologically substantiate the complete response to telatinib.Experimental Design: As the fusion results in overexpression of a truncated form of FOSB, we overexpressed truncated FOSB in normal endothelial cells.Results: Truncated FOSB significantly affected tumor growth in three-dimensional (3D) on matrigel with increased and sustained sprouting. Moreover, truncated FOSB acted as an active transcription factor capable to regulate its own transcription, as well as to upregulate PDGFRA and FLT1 expression (four-fold). Telatinib decreased proliferation and tumor growth in 3D and induced apoptosis. As expected, telatinib blocked VEGF signaling as phosphorylation of ERK was abolished. Interestingly, in FOSB overexpressing cells, telatinib specifically affected PDGFRA, FLT1, and FLT4 signaling and downregulated SERPINE1, thereby affecting the self-regulation of the fusion gene.Conclusions: We provide a biological substantiation of a complete clinical remission that was seen in a patient with PHE, showing that telatinib indirectly interferes with the self-regulated expression of the fusion product. Thus, telatinib or any other currently available VEGFR1-4/PDGFRA inhibitor could be a highly specific treatment option for patients with multifocal unresectable PHE. Clin Cancer Res; 24(11); 2678-87. ©2018 AACR.

[Characteristics of ERG, Fli-1, CD34, CD31 and Fâ §RAg expression in hepatic malignant vascular tumors].

Objective: To investigate the expression of ERG, Fli-1, CD34, CD31 and factor Ⅷ-related antigen(FⅧRAg) in hepatic malignant vascular tumors. Methods: A retrospective analysis was conducted on 63 cases of primary hepatic malignant vascular tumors and 31 cases of hepatic other malignant spindle cell tumors collected during January 1986 to January 2014. EnVision method was used to detect the expression of ERG, Fli-1, CD34, CD31, FⅧRAg. Results: Sixty-three cases of malignant vascular tumors, including 24 cases of angiosarcoma, 38 cases of epithelioid hemangioendothelioma and 1 case of hepatic Kaposi's sarcoma. All of the cases were positive for ERG(100.0%, 63/63). Positive rate of Fli-1, CD34, CD31, FⅧRAg was 96.8% (61/63), 87.3% (55/63), 81.0% (51/63) and 41.3% (26/63), respectively. In other hepatic malignant spindle cell tumors, the positive rate of ERG, Fli-1, CD34, CD31 and FⅧRAg was 3.2% (1/31), 19.4% (6/31), 19.4% (6/31), 9.7%(3/31) and 3.2%(1/31), respectively.The sensitivity of ERG, Fli-1, CD34, CD31, FⅧRAg was 100.0%, 96.8%, 87.3%, 81.0% and 41.3%, respectively.The specificity was 96.8%, 80.6%, 80.6%, 90.3% and 96.8%, respectively. Conclusion: ERG is a more sensitive and specific diagnostic marker for hepatic malignant vascular tumors in comparison to Fli-1, CD34, CD31 and FⅧRAg.

68Ga-DOTA-TATE PET/CT for Molecular Imaging of Somatostatin Receptor Expression in Metastasizing Epithelioid Hemangioendothelioma: Comparison With 18F-FDG.

Epithelioid hemangioendothelioma (EHE) is a rare tumor originating from vascular endothelial or pre-endothelial cells. It has the potential to metastasize. We present the case of a 51-year-old woman with metastasizing EHE who underwent both F-FDG and Ga-DOTA-TATE PET/CT for staging of disease and for evaluation of targeted radionuclide therapy potential. On Ga-DOTA-TATE PET scans, intense tracer accumulation was observed in metastases. Besides the increased glucose metabolism in EHE, this case highlights the potential of Ga-DOTA-TATE PET/CT for restaging of EHE and the option of targeted radionuclide therapy in this entity.

[Hypercalcemia related to PTH-rP revealing malignant hepatic epithelioid hemangioendothelioma]. / Une hypercalcémie humorale maligne révélant un hémangioendothéliome épithélioïde du foie.

Hypercalcemia caused by tumor production of PTH-rp occurs most often in cases of squamous cell carcinoma of the lung, aerodigestive tract cancer, gynecological cancer and lymphoma. We report an exceptional case of PTH-rp related to a hepatic hemangioendothelioma. A 70 years-old male admitted for deterioration of the general state. The laboratory investigations revealed hypercalcemia, related to tumor production of PTH-rp. Imaging revealed tumoral hepatic lesions. Histopathological study and immunohistochemistry showed diffuse response for CD31 marker, CK20 (+) with CK7 (-) and hepatocyt antigen (-). The diagnosis of PTH-rp related to hepatic hemangioendothelioma was make. The patient died with recurrence of fatal hypercalcemia. Management of patients presenting with humoral hypercalcemia includes a vigorous search for tumor lesions. Elevated PTH-rp can be a bad prognostic factor. In front of tumoral liver lesions, a hepatic epithelioid hemangioendothelioma must be considered. Immunohistochemistry is necessary to make diagnosis.

[Epithelioid hemangioendothelioma: a clinicopathologic analysis of 13 cases].

OBJECTIVE: To investigate the clinicopathologic characteristics of epithelioid hemangioendothelioma (EHE). METHODS: Thirteen cases of EHE were analyzed by gross examination, light microscopy and immunohistochemical staining. RESULTS: The patients included 6 males and 7 females. The age of patients ranged from 11 to 74 years (mean = 43 years). The tumors were located in soft tissue, liver, lung, mediastinum, sacrum, and pleura. The tumor cells were epithelioid, spindled or polygonal-shaped and exhibited cord-like or small nest growth pattern. Some tumor cells formed cytoplasmic vacuoles, which contained erythrocytes. The tumor cells showed abundant eosinophilic cytoplasm. The stroma varied from highly myxoid to hyaline. In 3 cases, the tumors contained areas with significant atypia, brisk mitotic activity and necrosis. Immunohistochemical study showed that the tumor cells were positive for CD31, ERG, FLI-1, CD34, factor VIII and CKpan to different extents. Follow-up information was available in 10 patients with duration ranging from 8 to 65 months. Seven patients were alive and three died. CONCLUSIONS: EHE is easily a rare maligant vascular tumor,occurs in many organs other than soft tissue.EHE is misdiagnosed as carcinoma for its significant epithelioid morphology. Recognizing its clinicopathologic characteristics and combined application of specific vascular endothelial immunohistochemical markers are important to avoid confusion with other lesions.

CAMTA1 is a useful immunohistochemical marker for diagnosing epithelioid haemangioendothelioma.

AIMS: The diagnosis of epithelioid haemangioendothelioma (EHE) is usually straightforward, based on characteristic histological features. However, it is sometimes difficult to differentiate EHE from a variety of other tumours with epithelioid morphology. The WW domain-containing transcription regulator 1-calmodulin-binding transcription activator 1 (WWTR1-CAMTA1) fusion gene, resulting in the overexpression of CAMTA1, is demonstrated in approximately 90% of EHEs, and the yes-associated protein 1-transcription factor E3 (YAP1-TFE3) fusion gene, associated with the strong and diffuse nuclear expression of TFE3, is present in another small subset of EHEs. The aim of our study was to examine CAMTA1 expression in EHEs and a variety of other tumours to evaluate its diagnostic utility, and to analyse TFE3 expression status in EHEs. METHODS AND RESULTS: Immunohistochemistry was performed on 16 EHEs, including five cases with CAMTA1 rearrangement and 276 non-EHE tumours. Fourteen of 16 EHEs and only one case of ductal carcinoma of the breast were positive for CAMTA1 and its expression was focal and weak in the latter (sensitivity 87.5%, specificity 99.6%). TFE3 expression was expressed focally and weakly in three (19%) EHEs (two with the CAMTA1 rearrangement). CONCLUSIONS: Nuclear CAMTA1 expression is sensitive and highly specific for EHE and can be applied to diagnostic immunohistochemistry in epithelioid tumours.

CD30 expression in malignant vascular tumors and its diagnostic and clinical implications: a study of 146 cases.

Angiosarcoma (AS) is a rare malignant vascular tumor, whereas epithelioid hemangioendothelioma (EHE) is a vascular tumor of low-grade malignancy. CD30 is a member of the tumor necrosis factor receptor superfamily, member 8 (TNFRSF8). Although the expression of CD30 is most commonly associated with lymphoid malignancies or germ cell tumors, occasional ASs have been reported as CD30 positive. However, there are limited data to evaluate its role definitively in malignant vascular tumors. In this study, we evaluated 91 ASs, 30 EHEs from various sites, and 25 Kaposi sarcomas. Overall, CD30 was expressed in 31/91 cases (34%) of AS, in 7/30 cases (30%) of EHE, but in none of the Kaposi sarcomas. CD30 was expressed in a membranous staining pattern and positivity in tumor cells varied from focal to diffuse. The positive ASs included vasoformative more differentiated tumors and also solid, undifferentiated, lymphoma-like examples, one of which was classified as lymphoma before the era of immunohistochemistry. The CD30 expression was seen in >50% of tumor cells in a majority of ASs but only in 7% of EHEs. None of the 55 ASs studied were immunohistochemically positive for TIA-1 or Granzyme B, antigens used as more specific markers for anaplastic large-cell lymphoma. Compared with AS, normal vascular endothelia of capillaries and muscular vessels showed variable positivity. Among hemangiomas, cavernous and spindle cell hemangiomas showed most frequent endothelial CD30 positivity, whereas in most other hemangiomas, CD30 positivity was scant. In conclusion, CD30 expression occurs in a significant subset of ASs and EHEs and needs to be included in the differential diagnosis with other CD30-positive malignancies to avoid a diagnostic pitfall. It remains to be determined whether patients with strongly CD30-positive ASs could be candidates for targeted therapy using the recently introduced CD30 antibody drug conjugates.