Alteration of PDGFRβ-Akt-mTOR pathway signaling in fibrosarcomatous transformation of dermatofibrosarcoma protuberans

Multi-omic profiling and real time ex vivo modelling of imatinib-resistant dermatofibrosarcoma protuberans with fibrosarcomatous transformation

Dermatofibrosarcoma protuberans (DFSP) is a rare and indolent cutaneous sarcoma, with the risk of aggressive fibro-sarcomatous transformation. Limited effective options are available for un-resectable or metastatic DFSP beyond targeting the oncogenic PDGF pathway with imatinib therapy. We established a patient-derived xenograft (PDX) and cell line model (designated MDFSP-S1) of imatinib-resistant DFSP with fibro-sarcomatous transformation. Whole genome sequencing identified high-level amplification at chromosomes 17 and 22, whilst homozygous deep deletion was demonstrated at chromosome 9 (CDKN2A, CDKN2B, MTAP). RNA sequencing followed by Sanger sequencing confirmed the pathognomonic COL1A1-PDGFB t (17;22) rearrangement in the original tumour, PDX and cell line model. Immunohistochemistry profiles of the PDX model were consistent with the patient's tumour sample (CD34 + /MIB1 + /SOX10- ). Gene set enrichment analysis highlighted top-scoring Hallmark gene sets in several oncogenic signalling pathways, including potentially targetable MTORC1 signalling and angiogenesis pathways. Antiangiogenic agents (sunitinib, regorafenib, pazopanib, axitinib) and the third-generation irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor osimertinib exhibited modest anti-proliferative activity in the cell line, with IC50 values between 1 and 10 µM at 72 h. No significant activity was observed with imatinib, palbociclib, everolimus, olaparib, gefitinib and erlotinib (IC50 all > 10 µM). In conclusion, we established MDFSP-S1, a new PDX and cell line model of imatinib-resistant DFSP with fibro-sarcomatous transformation.

Coamplification of 12q15 and 12p13 and homozygous CDKN2A/2B deletion: synergistic role of fibrosarcomatous transformation in dermatofibrosarcoma protuberans with a cryptic COL1A1-PDGFB fusion

Dermatofibrosarcoma protuberans (DFSP) is characterized by collagen type I alpha 1 chain-platelet-derived growth factor B chain (COL1A1-PDGFB) fusion. We present a case of fibrosarcomatous DFSP with lung metastasis in a 53-year-old man. Histologically, the primary and metastatic tumors were composed of high-grade fibrosarcomatous component with varying myxoid changes, while only a small focus of the classic DFSP element was identified in the primary lesion. No evidence of COL1A1-PDGFB fusion was identified by routine fluorescence in situ hybridization (FISH). Subsequent next-generation sequencing and COL1A1 break-apart FISH identified the fusion. In addition, coamplification of 12q15 and 12p13, along with CDKN2A/2B deletion, was confirmed to be limited to the fibrosarcomatous component. The current case is a novel FS-DFSP with cryptic COL1A1-PDGFB fusion. This is the first published example of DFSP harboring coamplification of 12q and 12p sequences. More importantly, the genetic aberrations restricted to the fibrosarcomatous component indicated a synergistic role of higher-grade progression.

Candidate Biomarkers for Specific Intraoperative Near-Infrared Imaging of Soft Tissue Sarcomas: A Systematic Review

Simple Summary

Near-infrared imaging of tumors during surgery facilitates the oncologic surgeon to distinguish malignant from healthy tissue. The technique is based on fluorescent tracers binding to tumor biomarkers on malignant cells. Currently, there are no clinically available fluorescent tracers that specifically target soft tissue sarcomas. This review searched the literature to find candidate biomarkers for soft tissue sarcomas, based on clinically used therapeutic antibodies. The search revealed 7 biomarkers: TEM1, VEGFR-1, EGFR, VEGFR-2, IGF-1R, PDGFRα, and CD40. These biomarkers are abundantly present on soft tissue sarcoma tumor cells and are already being targeted with humanized monoclonal antibodies. The conjugation of these antibodies with a fluorescent dye will yield in specific tracers for image-guided surgery of soft tissue sarcomas to improve the success rates of tumor resections.

Abstract

Surgery is the mainstay of treatment for localized soft tissue sarcomas (STS). The curative treatment highly depends on complete tumor resection, as positive margins are associated with local recurrence (LR) and prognosis. However, determining the tumor margin during surgery is challenging. Real-time tumor-specific imaging can facilitate complete resection by visualizing tumor tissue during surgery. Unfortunately, STS specific tracers are presently not clinically available. In this review, STS-associated cell surface-expressed biomarkers, which are currently already clinically targeted with monoclonal antibodies for therapeutic purposes, are evaluated for their use in near-infrared fluorescence (NIRF) imaging of STS. Clinically targeted biomarkers in STS were extracted from clinical trial registers and a PubMed search was performed. Data on biomarker characteristics, sample size, percentage of biomarker-positive STS samples, pattern of biomarker expression, biomarker internalization features, and previous applications of the biomarker in imaging were extracted. The biomarkers were ranked utilizing a previously described scoring system. Eleven cell surface-expressed biomarkers were identified from which 7 were selected as potential biomarkers for NIRF imaging: TEM1, VEGFR-1, EGFR, VEGFR-2, IGF-1R, PDGFRα, and CD40. Promising biomarkers in common and aggressive STS subtypes are TEM1 for myxofibrosarcoma, TEM1, and PDGFRα for undifferentiated soft tissue sarcoma and EGFR for synovial sarcoma.

Clinicopathological features of fibrosarcomatous dermatofibrosarcoma protuberans and the construction of a back-propagation neural network recognition model

BACKGROUND

Fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) is a form of tumor progression of dermatofibrosarcoma protuberans (DFSP) with an increased risk of metastasis and recurrence. Few studies have compared the clinicopathological features of FS-DFSP and conventional DFSP (C-DFSP).

OBJECTIVES

To better understand the epidemiological and clinicopathological characteristics of FS-DFSP.

METHODS

We conducted a cohort study of 221 patients diagnosed with DFSP and built a recognition model with a back-propagation (BP) neural network for FS-DFSP.

RESULTS

Twenty-six patients with FS-DFSP and 195 patients with C-DFSP were included. There were no differences between FS-DFSP and C-DFSP regarding age at presentation, age at diagnosis, sex, size at diagnosis, size at presentation, and tumor growth. The negative ratio of CD34 in FS-DFSP (11.5%) was significantly lower than that in C-DFSP (5.1%) (P = 0.005). The average Ki-67 index of FS-DFSP (18.1%) cases was significantly higher than that of C-DFSP (8.1%) cases (P < 0.001). The classification accuracy of the BP neural network model training samples was 100%. The correct rates of classification and misdiagnosis were 84.1% and 15.9%.

CONCLUSIONS

The clinical manifestations of FS-DFSP and C-DFSP are similar but have large differences in immunohistochemistry. The classification accuracy and feasibility of the BP neural network model are high in FS-DFSP.

Comparative expression profile of CD10 and cyclin D1 in cutaneous histiocytofibroma and dermatofibrosarcoma

Dermatofibrosarcoma protuberans (DFSP) and histiocytofibroma (HF) are two rare fibrohistiocytic tumors, with some overlapping pathologic features. Immunohistochemistry is very useful in these cases. CD34 is a commonly used marker. However, the increasing cases of CD34 negative DFSP make it pressing to test other immunohistochemical markers that could help in the differential diagnosis. DFSP is known to harbor COL1A1-PDGFB rearrangement. Tumors in the differential diagnosis of DFSP usually lack this molecular signature. Recent studies suggested the interaction of PDGFB and PDGF receptor b with various signaling pathways, including the Akt-mTOR pathway. Cyclin D1, one of the oncoproteins activated in this pathway, may represent a promising useful biomarker in the differential diagnosis. On the other hand, CD10 expression in specialized mesenchymal skin cells, and especially in fibrohistiocytic skin tumors has been reported, which raises the interest of using this biomarker in HF and DFSP. In this study, we aimed to compare the expression of CD10 and cyclin D1 in 15 cases of DFSP and 15 cases of HF and discuss their potential contribution in the differential diagnosis.

Dermatofibrosarcoma Protuberans: Update on the Diagnosis and Treatment

Dermatofibrosarcoma protuberans (DFSP) is a slow growing, low- to intermediate-grade dermal soft-tissue tumor. It has a high local recurrence rate but low metastatic potential. It is characterized by a uniform spindle cell arrangement, classically with a storiform pattern and CD34 immunoreactivity. The histomorphology and immunophenotype overlap with a broad range of other neoplasms. The standard treatment is complete surgical excision. The surgical procedures include wide local excision (WLE) with tumor free margins, Mohs micrographic surgery (MMS) and amputation. Unresectable DFSPs are treated with radiation therapy and/or targeted therapy. DFSP has characteristic t(17; 22) (q22; q13), resulting in a COL1A1- PDGFB fusion transcripts in more than 90% of DFSPs. Molecular detection of the gene rearrangement or fusion transcripts is helpful for the diagnosis of patients with atypical morphology and for screening candidates for targeted therapy with tyrosine kinase inhibitors. The aims of the present review are to update the clinical presentation, tumorigenesis and histopathology of DFSP and its variants for diagnosis and differential diagnosis from other benign and malignant tumors, to compare the advantages and drawbacks of WLE and MMS, to propose the baseline for selecting surgical procedure based on tumor's location, size, stage and relationship with surrounding soft tissue and bone structures, and to provide a biologic rationale for the systemic therapy. We further propose a modified clinical staging system of DFSP and a surveillance program for the patients after surgical excision.

Dermatofibrosarcoma protuberans in children and adolescents: Primary and Relapsed disease-Experience of the Cooperative Weichteilsarkomstudiengruppe (CWS)

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade tumor. Little is known about best treatment of primary and relapsed disease (RD).

METHODS

Treatment and outcome of 40 patients with DFSP prospectively registered within the CWS-96 and -2002P trials and the registry SoTiSaR (1996-2016) were analysed.

RESULTS

Median age was 8 years (range, 0.64-17.77). Fluorescence in situ hybridization analysis to detect COL1A1-PDGFB fusion genes was positive in 86% (12/14) of evaluated patients. Primary resection was performed in all patients. Patients had IRS group I (n = 28), II (n = 9), and III (n = 2); not available (n = 1). To achieve complete remission (CR), a secondary resection was performed in 18 patients resulting in microscopically complete (R0, n = 34/40) and microscopically incomplete (R1, n = 5/40) resection. All patients achieved CR. The 5-year event-free survival (EFS) and overall survival was 86% (±12; CI, 95%) and 100% (±0; CI, 95%), respectively. R0 resection/IRS I was significantly favorable for the 5-year EFS. Local relapse occurred after a median time of 1.1 years (range, 0.04-5.1) in 15% (6/40) after CR. All patients with RD underwent resection and achieved CR. Three patients had fibrosarcomatous DFSP, two were alive after R0 resection.

CONCLUSION

Complete surgical resection is mandatory to prevent relapse of DFSP.

Dermatofibrosarcoma protuberans with fibrosarcomatous transformation arising at the site of breast implant

Fibrosarcomatous transformation of dermatofibrosarcoma protuberans (DFSP) is a rare variant with higher risk of recurrence and metastasis, and no known associations with breast implants. We report a rare case of fibrosarcomatous dermatofibrosarcoma protuberans arising at the site of breast implant in a 33-year-old patient followed by brief discussion on fibrosarcomatous DFSP.

Current Update on the Molecular Biology of Cutaneous Sarcoma: Dermatofibrosarcoma Protuberans

OPINION STATEMENT

Cutaneous sarcoma is a group of malignant mesenchymal tumors primarily involving the dermis, and it is characterized by extreme clinicopathological heterogeneity. Although its occurrence rate is rare, dermatofibrosarcoma protuberans (DFSP) is one of the most common types of dermal sarcoma. DFSP grows slowly and tends to relapse locally after inadequate resection. There are various histological variants of DFSP tumors and it often mimics benign lesions such as dermatofibroma and scar, which make accurate diagnosis difficult and delayed, and some cases progress to the stage where the tumor is unresectable. Recent advancements in cancer genetics and molecular biology methods have elucidated the COL1A1-PDGFB fusion gene, some novel fusion gene variants and pathways related to DFSP pathogenesis that have resulted in the evolution of cutaneous sarcoma diagnosis and treatment. For example, some clinical studies have confirmed the efficacy of imatinib methylate, an αPDGFR-targeted therapy for unresectable or metastatic DFSP. The present review summarizes recent updates in DFSP research, diagnostics, and treatment.

Dermatofibrosarcoma protuberans – the impact of radiation therapy: a single institution series

Background

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive intermediate malignancy.

Objective

The purpose of this retrospective analysis is to determine the efficacy of radiation therapy (RT) in local control of DFSP.

Patients and methods

The recurrence-free survival (RFS) for 45 patients treated for DFSP at our institution was estimated and compared between surgery alone and postoperative RT groups.

Results

Age range of the patients were in the third and fourth decades; males:females=2:1; most common site: anterior abdominal wall; tumours >5 cm in size in 75%; low grade in 77·8%; margins positive in 31·8% and <5 mm margins in 45·5%. Two-thirds of patients had at least one recurrence before presentation to our institution. RT dose was >50 Gy in 88% of patients. The patients treated with postoperative RT had poorer prognostic factors compared with surgery alone: they were males (17 versus 13 patients), and presented with high-grade tumours (5 versus 1 patients), multiple recurrences prior to presentation (25 versus 20 patients) and positive or <5 mm margins (22 versus 12 patients). Median follow-up for surgery alone group was 17 (1–152) months and for postoperative RT group, this was 54 (5–121) months. RFS at 5 years was 77·1% for surgery alone and 87·9% for postoperative RT group but was not statistically significant. The median time to recurrence was 4 years.

Conclusion

RT delays the time to recurrence in DFSP. RT improves the outcome of DFSP for recurrent tumours and with positive margins.

Dermatofibrosarcoma Protuberans: Retrospective Single Center Analysis Over 16 Years

Dermatofibrosarcoma protuberans (DFSP) is rare mesenchymal neoplasia with a high risk of local recurrence but a low risk of metastatic spread. Tumor cells express CD34 and show a characteristic translocation t(17;22)(q22;q13). We analysed the documented cases at the Department of Dermatology and Allergology between 08/2001 and 08/2017. The diagnosis had been confirmed by histology and immunohistology in all cases. We identified four adults and a pediatric patient with DFSP. All patients were treated by wide surgical excision and controlled by three-dimensional histologic margin control. We observed no recurrence and no metastatic spread. We discuss prognostic factors and emerging treatments.