Marie Karanian

Fluorescence in situ hybridization analysis is a helpful test for the diagnosis of dermatofibrosarcoma protuberans

Cytogenetically, most dermatofibrosarcoma protuberans are characterized by chromosomal rearrangements resulting in the collagen type-1 alpha 1 (COL1A1)–platelet-derived growth factor β (PDGFB) fusion gene. This abnormality can be detected by fluorescence in situ hybridization (FISH) analysis in routine practice. The aim of this study was to evaluate the role of the FISH analysis in the diagnosis of dermatofibrosarcoma protuberans. A FISH analysis was prospectively and systematically performed on a series of 448 consecutive tumor specimens. All cases were reviewed by two independent pathologists and classified in three categories according to the probability of a DFSP diagnosis before molecular analyses. Cases were classified as certain when dermatofibrosarcoma protuberans was the only possible diagnosis. Those cases for which dermatofibrosarcoma protuberans remained the first diagnosis, but other differential diagnosis existed, were regarded as probable. When dermatofibrosarcoma protuberans was considered a differential diagnosis, they were labeled as possible. The final diagnosis was supported by clinicopathological findings and results of FISH analyses. Immunohistochemical analysis of CD34 was systematically performed, and additional markers when necessary. The cases (n=37) with a non-interpretable FISH were excluded. For the 185 certain tumors specimens: 178 (96%) FISH analyses showed a PDGFB/COL1A1 rearrangement, 7 (4%) were negative. For the 114 probable tumors specimens: 104 (91%) FISH analyses were positive and 10 (9%) were negative leading to a new diagnosis in 8 cases. For the 112 possible cases: 91 (81%) FISH analyses were negative and 21 (19%) were positive. Of the 21 cases, initial diagnoses included unclassified sarcoma, myxofibrosarcoma, dermatofibroma, reactive lesion, solitary fibrous tumor, perineurioma, benign nerve sheath tumor, and undifferentiated spindle cell tumor without malignant evidence. FISH analysis has been helpful for confirming the diagnosis of dermatofibrosarcoma protuberans in 25% (104/411) of cases and necessary for the diagnosis of dermatofibrosarcoma protuberans in 5% (21/411) of cases.

Transcriptomic definition of molecular subgroups of small round cell sarcomas: Molecular classification of sarcoma subtypes

Sarcoma represents a highly heterogeneous group of tumours. We report here the first unbiased and systematic search for gene fusions combined with unsupervised expression analysis of a series of 184 small round cell sarcomas. Fusion genes were detected in 59% of samples, with half of them being observed recurrently. We identified biologically homogeneous groups of tumours such as the CIC‐fused (to DUX4, FOXO4 or NUTM1) and BCOR‐rearranged (BCOR–CCNB3, BCOR–MAML3, ZC3H7B–BCOR, and BCOR internal duplication) tumour groups. VGLL2‐fused tumours represented a more biologically and pathologically heterogeneous group. This study also refined the characteristics of some entities such as EWSR1–PATZ1 spindle cell sarcoma or FUS–NFATC2 bone tumours that are different from EWSR1–NFATC2 tumours and transcriptionally resemble CIC‐fused tumour entities. We also describe a completely novel group of epithelioid and spindle‐cell rhabdomyosarcomas characterized by EWSR1– or FUS–TFCP2 fusions. Finally, expression data identified some potentially new therapeutic targets or pathways. Copyright

MDM2 antagonists synergize with PI3K/mTOR inhibition in well-differentiated/dedifferentiated liposarcomas

Background Well-differentiated/dedifferentiated liposarcoma (WDLPS/DDLPS) are characterized by a consistent amplification of the MDM2 gene. The PI3K/AKT/mTOR pathway has been suggested to play also an important role in their tumorigenesis. Our goal was to determine whether combined MDM2 and PI3K/AKT/mTOR targeting is associated with higher anti-tumor activity than single agent alone in preclinical models of WDLPS/DDLPS. Methods WDLPS/DDLPS cells were exposed to RG7388 (MDM2 antagonist) and BEZ235 (PI3K/mTOR dual inhibitor) after which apoptosis and signaling/survival pathway perturbations were monitored by flow cytometry and Western blot analysis. Xenograft mouse models were used to assess tumor growth and animal survival. Western blotting, histopathology, and tumor volume evolution were used for the assessment of treatment efficacy. Results The PI3K/AKT/mTOR was upregulated in up to 81% of the human WDLPS/DDLPS samples analysed. Treatment with RG7388 and BEZ235 resulted in a greater tumor activity than either drug alone with a significant difference in terms of cell viability after 72h of treatment with RG-73888 alone, BEZ235 alone and a combination of both agents. Consistent with these observations, we found a significant increase in apoptosis with the combination versus the single agent treatment alone. We then analysed the in vivo antitumor activity of RG7388 and BEZ235 in a xenograft model of DDLPS. The combination regimen significantly reduced tumor growth rate in comparison with single agent alone. Conclusions Our results represent the first in vivo evidence of synergy between MDM2 and PI3K/AKT/mTOR antagonists and represent a strong rationale to evaluate the therapeutic potential of such a combination in WDLPS/DDLPS.BACKGROUND Well-differentiated/dedifferentiated liposarcoma (WDLPS/DDLPS) are characterized by a consistent amplification of the MDM2 gene. The PI3K/AKT/mTOR pathway has been suggested to play also an important role in their tumorigenesis. Our goal was to determine whether combined MDM2 and PI3K/AKT/mTOR targeting is associated with higher anti-tumor activity than single agent alone in preclinical models of WDLPS/DDLPS. METHODS WDLPS/DDLPS cells were exposed to RG7388 (MDM2 antagonist) and BEZ235 (PI3K/mTOR dual inhibitor) after which apoptosis and signaling/survival pathway perturbations were monitored by flow cytometry and Western blot analysis. Xenograft mouse models were used to assess tumor growth and animal survival. Western blotting, histopathology, and tumor volume evolution were used for the assessment of treatment efficacy. RESULTS The PI3K/AKT/mTOR was upregulated in up to 81% of the human WDLPS/DDLPS samples analysed. Treatment with RG7388 and BEZ235 resulted in a greater tumor activity than either drug alone with a significant difference in terms of cell viability after 72h of treatment with RG-73888 alone, BEZ235 alone and a combination of both agents. Consistent with these observations, we found a significant increase in apoptosis with the combination versus the single agent treatment alone. We then analysed the in vivo antitumor activity of RG7388 and BEZ235 in a xenograft model of DDLPS. The combination regimen significantly reduced tumor growth rate in comparison with single agent alone. CONCLUSIONS Our results represent the first in vivo evidence of synergy between MDM2 and PI3K/AKT/mTOR antagonists and represent a strong rationale to evaluate the therapeutic potential of such a combination in WDLPS/DDLPS.

Cutaneous Melanocytoma With : Report of 5 Cases Resembling Clear Cell Sarcoma crtc1-trim11 : Report of 5 Cases Resembling Clear Cell Sarcoma Fusion: Report of 5 Cases Resembling Clear Cell Sarcoma

We report 5 cases of primary intradermal nodular unpigmented tumors with a melanocytic immunophenotype associated with a novel CRTC1-TRIM11 fusion. Clinically, the cutaneous nodules were slowly growing in 3 women and 2 men (25 to 82 y old, median, 28 y) with no specific topography. Lesion size ranged from 4 to 12 mm (median, 5 mm). The tumors were strictly located in the dermis with a nodular pattern. The cells were arranged in confluent nests and fascicules. Central fibronecrotic areas were present in 2 cases. Cells were medium to large, sometimes multinucleated, and presented a spindled and epithelioid cytology with prominent nucleoli. Cytonuclear atypia was constant, and mitotic activity in hotspot areas ranged from 1 to 5/mm². Immunohistochemistry found a constant positivity with S100, MiTF, and Sox10, and a heterogenous staining by MelanA or HMB45. NTRK1 was strongly positive in 3 cases. In all cases, RNA sequencing found an invariable CRTC1(e1)-TRIM11(e2) fusion, confirmed by fluorescent in situ hybridization techniques with a TRIM11 break-apart probe. In 4/4 cases, nuclear TRIM11 expression was positive by immunohistochemistry. Fluorescent in situ hybridization techniques showed no rearrangement of NTRK1 or EWSR1, and array-comparative genomic hybridization displayed no alteration (1 case) or only a whole chromosome 7 gain (2 cases) when performed. No relapse or metastatic event was observed during follow-up [3 to 72 months (median, 14 mo)]. Cutaneous clear cell sarcoma was the main differential diagnosis. Overlapping morphologic features previously described in primary dermal melanomas and paraganglioma-like melanocytic tumors were present. The CRTC1-TRIM11 fusion appears to be specific of an unpigmented nodular tumor combining a melanocytic phenotype and low-grade tumor behavior.

Alternative PDGFD rearrangements in dermatofibrosarcomas protuberans without PDGFB fusions

Dermatofibrosarcoma protuberans is underlined by recurrent collagen type I alpha 1 chain-platelet-derived growth factor B chain(COL1A1-PDGFB) fusions but ~ 4% of typical dermatofibrosarcoma protuberans remain negative for this translocation in routine molecular screening. We investigated a series of 21 cases not associated with the pathognomonic COL1A1-PDGFB fusion on routine fluorescence in situ hybridization (FISH) testing. All cases displayed morphological and clinical features consistent with the diagnosis of dermatofibrosarcoma protuberans. RNA-sequencing analysis was successful in 20 cases. The classical COL1A1-PDGFB fusion was present in 40% of cases (n = 8/20), and subsequently confirmed with a COL1A1 break-apart FISH probe in all but one case (n = 7/8). 55% of cases (n = 11/20) displayed novel PDGFD rearrangements; PDGFD being fused either to the 5′ part of COL6A3 (2q37.3) (n = 9/11) or EMILIN2 (18p11) (n = 2/11). All rearrangements led to in-frame fusion transcripts and were confirmed at genomic level by FISH and/or array-comparative genomic hybridization. PDGFD-rearranged dermatofibrosarcoma protuberans presented clinical outcomes similar to typical dermatofibrosarcoma protuberans. Notably, the two EMILIN2-PDGFD cases displayed fibrosarcomatous transformation and homozygous deletions of CDKN2A at genomic level. We report the first recurrent molecular variant of dermatofibrosarcoma protuberans involving PDGFD, which functionally mimic bona fide COL1A1-PDGFB fusions, leading presumably to a similar autocrine loop-stimulating PDGFRB. This study also emphasizes that COL1A1-PDGFB fusions can be cytogenetically cryptic on FISH testing in a subset of cases, thereby representing a diagnostic pitfall that pathologists should be aware of.

Cutaneous inflammatory myofibroblastic tumours can be anaplastic lymphoma kinase-positive: report of the first four cases.

Inflammatory myofibroblastic tumours (IMTs) usually have a soft tissue and visceral localization, but have been rarely reported in skin. The aim of this study was to characterize the histological and immunohistochemical features of a series of cutaneous IMTs.

Using biology to guide the treatment of sarcomas and aggressive connective-tissue tumours

Sarcomas are a heterogeneous group of malignancies that arise from cells of a mesenchymal origin. Surgery forms the mainstay of the treatment of most patients with localized sarcoma and might be followed or preceded by chemotherapy and/or radiotherapy. In the metastatic setting, systemic treatments tend to improve survival and control symptoms. However, the adverse events and sometimes disappointing outcomes associated with these empirical approaches to treatment indicate a need for new approaches. The advent of next-generation sequencing (NGS) has enabled more targeted treatment of many malignancies based on the presence of specific alterations. NGS analyses of sarcomas have revealed the presence of many alterations that can be targeted using therapies that are already used in patients with other forms of cancer. In this Review, we describe the genomic alterations considered to define specific nosological subgroups of sarcoma and whose contribution to oncogenesis provides a biological rationale for the use of a specific targeted therapy. We also report several less successful examples that should guide researchers and clinicians to better define the extent to which the identification of driver molecular alterations should influence the development of novel treatments.Patients with sarcomas have historically been treated with surgery and/or chemotherapy, although the outcomes achieved with these approaches, especially in advanced-stage disease, are often disappointing. In this Review, the authors describe the opportunities created by selective use of targeted therapies on the basis of the biological characteristics of individual tumours.Key pointsCertain genomic alterations define specific nosological subgroups of sarcoma, and their contribution to oncogenesis provides a biological rationale for the use of a specific targeted therapy.Receptor tyrosine-kinase activation in gastrointestinal stromal tumours (GISTs) is a paradigmatic model in which the genomic characterization of a tumour provides information on diagnosis, prognosis, and response to treatment and enables improved patient outcomes.Translocation-related sarcomas constitute a classical subgroup of sarcoma; however, the translation of a specific fusion protein into an effective targeted treatment has sometimes proved difficult to achieve.Many therapeutic strategies are under development in an attempt to target other mechanisms of carcinogenesis, such as inactivation of tumour suppressor genes, gene amplification, or epigenetic dysregulation.Research strategies should attempt to increase the use of genomic screening and integrate analyses of multiple genomic events to guide treatment and continue to improve the outcomes of patients with sarcoma.

Outcome of 449 adult patients with rhabdomyosarcoma: an observational ambispective nationwide study

Five‐year overall survival (OS) of localized RMS exceeds 70% in children (<18) but is very poor in adult patients. We analyzed the outcome and prognostic factors (PF) of a national series of adult patients with RMS in a large study. The study population consisted of two different cohorts: a retrospective cohort (157 adult patients treated in 13 reference centers between 05/1981 and 02/2010) and the prospective cohort (292 patients with RMS diagnosed and treated between 01/2010 and 12/2014 in France) included in the NetSarc database. A descriptive analysis of patients’ characteristics and prognostic factors was conducted on both series which were compared. In the retrospective series, histological subtypes were embryonal (E‐RMS) for 21% of patients, alveolar (A‐RMS) for 35% of patients, and “adult‐type” P‐RMS (pleomorphic, spindle cell RMS, not otherwise specified) (P) for 44% patients. This distribution significantly differed in the prospective cohort: A‐RMS: 18%; E‐RMS: 17%; and P‐RMS 65%. With a median follow‐up of 8.5 years, 5‐year OS for localized RMS and advanced RMS (with nodes and/or metastases) was 43% and 5%, respectively, (P < 0.0001), and median OS was 51, 33, and 16 months for E‐RMS, A‐RMS, and P‐RMS, respectively, in the retrospective cohort. The median OS was less than 40 months for the prospective nationwide cohort for the entire population. In a multivariate analysis of the retrospective study, independent prognostic factors for OS were A‐RMS, R0 resection, and adjuvant radiotherapy (RT). For localized RMS, age and use of pediatric chemotherapy (CT) regimen are independent prognostic factors. Adult patients with RMS have a poorer overall survival than pediatric patients, and survival varies considerably across histological subtypes.

Dual inhibition of the PI3K/AKT/mTOR pathway suppresses the growth of leiomyosarcomas but leads to ERK activation through mTORC2: biological and clinical implications

The PI3K/AKT/mTOR pathway plays a crucial role in the development of leiomyosarcomas (LMSs). In this study, we tested the efficacy of dual PI3K/mTOR (BEZ235), PI3K (BKM120) and mTOR (everolimus) inhibitors in three human LMS cell lines. In vitro and in vivo studies using LMS cell lines showed that BEZ235 has a significantly higher anti-tumor effect than either BKM120 or everolimus, resulting in a greater reduction in tumor growth and more pronounced inhibitory effects on mitotic activity and PI3K/AKT/mTOR signaling. Strikingly, BEZ235 but neither BKM120 nor everolimus markedly enhanced the ERK pathway. This effect was reproduced by the combination of BKM120 and everolimus, suggesting the involvement of mTORC2 via a PI3K-independent mechanism. Silencing of RICTOR in LMS cells confirmed the role of mTORC2 in the regulation of ERK activity. Combined treatment with BEZ235 and GSK1120212, a potent MEK inhibitor, resulted in synergistic growth inhibition and apoptosis induction in vitro and in vivo. These findings document for the first time that dual PI3K/mTOR inhibition in leiomyosarcomas suppress a negative feedback loop mediated by mTORC2, leading to enhanced ERK pathway activity. Thus, combining a dual PI3K/mTOR inhibitor with MEK inhibitors may be a relevant approach to increase anti-tumor activity and prevent drug resistance in patients with LMS.

Abstract 4636: Dual targeting of PI3K/mTOR leads to MEK/ERK over-activation in leiomyosarcoma through suppression of mTORC2 inhibition

Leiomyosarcoma (LMS) are an uncommon group of malignant tumors composed of cells showing smooth muscle differentiation that represent 10-15% of all soft-tissue sarcomas and is therefore one of the most frequent sarcoma subtype. From a genetic point of view, LMS are characterized by numerous genomic alterations whose a large region of deletion on chromosome 10 including the tumor suppressor gene PTEN. It is one of the most frequent aberration (40-50% of cases) and is associated with increased activation of the mTOR pathway. Moreover, in vitro and vivo studies have demonstrated that the mTOR pathway plays a crucial role in LMS tumorigenesis. There are no data about the role of PI3K/mTOR targeting in LMS. The LMS cell lines have been derived from human surgical STS specimens in our laboratory. Cells were treated for 72hrs with a range of increasing concentrations of Everolimus (mTORC1 inhibitor), BKM120 (PI3KCA inhibitor) and BEZ235 (dual PI3K-mTOR inhibitor) to assess anti-proliferative activity by MTT-assay and apoptosis by AnnexinV/PI staining. Effects on mTOR and MAPK pathway signaling were studied by western blot analysis. The LMS cell lines were exposed to increasing doses of BEZ235 in combination with GDC-0994 (ERK inhibitor) and synergy was assessed by Chou-Talalay combination index (CI). Effects of all inhibitors were observed in mice with subcutaneous LMS cell line-derived xenograft tumors for 3 weeks. Dose-dependent growth suppression was more clearly induced by BEZ235 (range, 0.001 to 0.1 μM) than by Everolimus and BKM120 (range 0.01 to 1.6 μM). Apoptosis was also much more effectively induced by BEZ235. We examined in vivo antitumor activity of the three drugs in mice inoculated with LMS cells. In vivo, the effects of BEZ235 (70% tumor volume [TV] inhibition versus untreated tumors) was also higher than that of BKM120 and Everolimus (30% and 55% TV inhibition). We assessed the effects of BEZ235 on signaling pathways in all cell lines. Strikingly, mTOR pathway was consistently repressed and BEZ235 markedly induced ERK overactivation. This effect was not observed with BKM120 or Everolimus suggesting a role of mTORC2. Knockdown of RICTOR via transfection of siRNA significantly reduced the enhancing effect of BEZ235 on ERK phosphorylation. Combined treatment with BEZ235 and GDC-0994, a potent ERK inhibitor, resulted in synergistic growth inhibition, apoptosis induction and decrease levels of both phosphorylated proteins of mTOR and ERK pathways in vitro and in vivo. Targeting PI3K and mTOR simultaneously using BEZ235 effectively inhibits LMS cell growth and prolongs survival of mice in comparison of those treated with BKM120 or Everolimus. However, BEZ235 suppress a negative feedback loop mediated by mTORC2, thereby leading to enhanced MEK/ERK pathway activity in LMSs cells. Combining BEZ235 with MEK/ERK inhibitors may be a relevant approach to increase anti-tumor activity and avoid drug resistance. Citation Format: Benjamin Fourneaux, Vanessa Chaire, Marie Karanian, Audrey Laroche, Antoine Italiano. Dual targeting of PI3K/mTOR leads to MEK/ERK over-activation in leiomyosarcoma through suppression of mTORC2 inhibition. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4636.