Expression of platelet-derived growth factor receptor in low-grade endometrial stromal sarcomas in the absence of activating mutations

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.

Endometrial Carcinoma: Specific Targeted Pathways

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.Several molecular alterations have been described in the different types of EC. They occur in genes involved in important signaling pathways. In this chapter, we will review the most relevant altered pathways in EC, including PI3K/AKT/mTOR, RAS-RAF-MEK-ERK, Tyrosine kinase, WNT/β-Catenin, cell cycle, and TGF-β signaling pathways. At the end of the chapter, the most significant clinical trials will be briefly discussed.This information is important to identify specific targets for therapy.

Systematic Analysis of Endometrial Cancer-Associated Hub Proteins Based on Text Mining

Objective. The aim of this study was to systematically characterize the expression of endometrial cancer- (EC-) associated genes and to analysis the functions, pathways, and networks of EC-associated hub proteins. Methods. Gene data for EC were extracted from the PubMed (MEDLINE) database using text mining based on NLP. PPI networks and pathways were integrated and obtained from the KEGG and other databases. Proteins that interacted with at least 10 other proteins were identified as the hub proteins of the EC-related genes network. Results. A total of 489 genes were identified as EC-related with P < 0.05, and 32 pathways were identified as significant (P < 0.05, FDR < 0.05). A network of EC-related proteins that included 271 interactions was constructed. The 17 proteins that interact with 10 or more other proteins (P < 0.05, FDR < 0.05) were identified as the hub proteins of this PPI network of EC-related genes. These 17 proteins are EGFR, MET, PDGFRB, CCND1, JUN, FGFR2, MYC, PIK3CA, PIK3R1, PIK3R2, KRAS, MAPK3, CTNNB1, RELA, JAK2, AKT1, and AKT2. Conclusion. Our data may help to reveal the molecular mechanisms of EC development and provide implications for targeted therapy for EC. However, corrections between certain proteins and EC continue to require additional exploration.

Frequent expression of KIT in endometrial stromal sarcoma with YWHAE genetic rearrangement

Endometrial stromal sarcomas with the YWHAE-NUTM2A/B genetic fusion characteristically contain high-grade round to epithelioid cell component that is strongly and diffusely cyclin D1-positive and it may or may not show an associated low-grade fibroblastic/myxoid cell component. They are clinically more aggressive than endometrial stromal sarcomas with the JAZF1-SUZ12 genetic fusion and frequently demonstrate extrauterine extension at initial clinical presentation. In this setting, the tumor may be misdiagnosed as gastrointestinal stromal tumor. This study examines the expression of KIT and ANO1 in 14 YWHAE-NUTM2A/B tumors by immunohistochemistry. Staining localization was determined as membranous and/or cytoplasmic, and the staining intensity was assessed (negative, weak, moderate and strong). Of the 14 tumors, 6 contained only a high-grade round cell component, 2 only a low-grade fibroblastic component and 6 had both components in the slides evaluated. The high-grade round cell component displayed moderate to strong membranous/cytoplasmic KIT staining in all tumors (12 of 12). The low-grade fibroblastic cell component showed only weak cytoplasmic KIT staining in 3 of 8 tumors. In contrast, ANO1 was negative in all 14 neoplasms, irrespective of the component evaluated. Sanger sequencing analysis (exons 9, 11, 13 and 17) and Ampliseq Cancer Panel mutation screen (Ion Torrent) demonstrated no KIT mutations in three KIT-positive YWHAE-NUTM2A/B tumors. This study shows that the high-grade round cell component of YWHAE-NUTM2A/B endometrial stromal sarcoma consistently expresses KIT but lacks KIT hotspot mutations. KIT expression may represent a potential diagnostic pitfall in the evaluation of YWHAE-NUTM2A/B endometrial stromal sarcoma presenting with pelvic/abdominal mass, particularly in situations where its uterine origin is not definitive, and thus a panel of antibodies that includes ANO1 and cyclin D1 is necessary.

Tyrosine kinase receptor status in endometrial stromal sarcoma: an immunohistochemical and genetic-molecular analysis

Endometrial stromal sarcomas (ESS) are rare uterine malignant mesenchymal neoplasms, which are currently treated by surgery, as effective adjuvant therapies have not yet been established. Tyrosine kinase inhibitors have rarely been applied in ESS therapy, with few reports describing imatinib responsivity. The aim of this study was to analyze the status of different tyrosine kinase receptors in an ESS series, in order to evaluate their potential role as molecular targets. Immunohistochemistry was performed for EGFR, c-KIT, PDGFR-α, PDGFR-β, and ABL on 28 ESS. EGFR, PDGFR-α, and PDGFR-β gene expression was investigated by real-time polymerase chain reaction (qRT-PCR) on selected cases. "Hot-spot" mutations were screened for on EGFR, c-KIT, PDGFR-α, and PDGFR-β genes, by sequencing. All analysis was executed from formalin-fixed, paraffin-embedded specimens. Immunohistochemical overexpression of 2 or more tyrosine kinase receptors was observed in 18 of 28 tumors (64%), whereas only 5 tumors were consistently negative. Gene expression profiles were concordant with immunohistochemical overexpression in only 1 tumor, which displayed both high mRNA levels and specific immunoreactivity for PDGFR-α, and PDGFR-β. No activating mutations were found on the tumors included in the study. This study confirms that TKRs expression is frequently observed in ESS. Considering that the responsiveness to tyrosine kinase inhibitors is known to be related to the presence of specific activating mutations or gene over-expression, which are not detectable in ESS, TKRs immunohistochemical over-expression alone should not be considered as a reliable marker for targeted therapies in ESS. Specific post-translational abnormalities, responsible for activation of TKRs, should be further investigated.

Endometrial stromal tumors: immunohistochemical and molecular analysis of potential targets of tyrosine kinase inhibitors

BACKGROUND

The systemic treatment of malignant endometrial stromal tumors (EST) is not well established. A few reports describe objective responses to imatinib, which suggest a novel therapeutic strategy for these tumors. Due to these facts, we aimed to perform a retrospective analysis of possible molecular targets of tyrosine kinase inhibitors (TKI) in EST: KIT, PDGFRA and EGFR.

METHODS

52 endometrial stromal sarcomas and 13 undifferentiated endometrial sarcomas were examined and reviewed. Mutational analysis were performed for exons 9, 11, 13, and 17 of the KIT gene, exons 12 and 18 of the PDGFRA gene and exons 18, 19, 20 and 21 of the EGFR gene. The incidence and distribution of the KIT, PDGFRA, and EGFR expression were examined by immunohistochemistry, and EGFR amplification was assessed by fluorescence in situ hybridization.

RESULTS

No mutations in KIT, PDGFRA and EGFR genes were detected. Overexpression of KIT, PDGFRA, EGFR, was detected in 2 (3%), 23 (35.4%), 7 (10.8%) cases respectively, whereas amplification of EGFR gene was not found.

CONCLUSIONS

Absence of significant expression, amplification and activating mutations on these tyrosine kinase receptors suggest that it is unlikely that EST can benefit from therapies such as TKI on the systemic setting.

Immunohistochemical Analysis for Therapeutic Targets and Prognostic Markers in Low-Grade Endometrial Stromal Sarcoma

Objective

To investigate potential therapeutic targets and prognostic markers for low-grade endometrial stromal sarcoma (LGESS).

Materials and Methods

Thirty-nine patients with LGESS were included in this study. Using tissue microarrays, the immunohistochemical expression levels of 5 therapeutic targets (epidermal growth factor receptor, human epidermal growth factor 2, vascular endothelial growth factor receptor, platelet-derived growth factor receptor [PDGFR], and c-kit) and 3 proteins involved in cell proliferation (p16, p53, and ki67) were investigated. The associations between these targets, markers, other clinicopathological factors, disease-free survival (DFS), and overall survival (OS) were analyzed.

Results

Epidermal growth factor receptor and human epidermal growth factor 2 were not expressed in these 39 patients. Vascular endothelial growth factor receptor, PDGFR, c-kit, p16, p53, and ki67 were expressed in 10 (25.6%), 28 (71.8%), 32 (82.1%), 18 (46.2%), 4 (10.3%), and 21 (53.8%) patients, respectively. The expression of each marker was not significantly associated with other clinicopathological factors. On multivariate analysis, p53 and ki67 were associated with significantly poorer DFS and OS. The 5-year DFS rates were 88%, 46%, and 0% for the p53(−)/ki67(−) group (n = 18), p53(−)/ki67(+) group (n = 17), and p53(+)/ki67(+) group (n = 4) (P = 0.002), respectively; the 5-year OS rates were 100%, 71%, and 0%, respectively (P < 0.001). The time to recurrence was longer (P = 0.123), and more patients had distant recurrence in the p53(+)/ki67(+) group (P = 0.063).

Conclusions

In patients with LGESS, c-kit and PDGFR were expressed in higher portions of patients, suggesting that imatinib mesylate should be investigated as a potential targeting agent. Both p53 and ki67 demonstrated strong prognostic implications, suggesting that further evaluation using these markers is required.

Recurrence patterns and prognosis of endometrial stromal sarcoma and the potential of tyrosine kinase-inhibiting therapy

OBJECTIVE

Endometrial stromal sarcoma (ESS) is a rare uterine malignancy. The current treatment approaches yield unsatisfactory results, and potential therapeutic targets need exploration.

METHODS

We reviewed the electronic medical records of 74 patients with low-grade ESS who had been evaluated at the University of Texas MD Anderson Cancer Center between 1995 and 2006. Using immunohistochemistry, we tested the expression of targets in paraffin-embedded tissue samples taken from 13 of the patients.

RESULTS

Forty-seven patients (64%) had a recurrence, and 16 (22%) had died of their disease at last follow-up. The 10-year progression-free survival (PFS) rate was 43% (median PFS duration, 108months), and the overall survival (OS) rate was 85% (median OS, 288months). Patients who received hormonal therapy had an overall response rate of 27%; another 53% had stable disease, with a median time to progression of 24months. No complete response or partial response was observed among patients who received radiotherapy or chemotherapy. In the paraffin-embedded specimens we tested, c-abl was expressed universally. Expression of PDGF-α, PDGF-β, VEGF, and c-Kit was detected in 33%, 36%, 54%, and 8%, of specimens, respectively. EGFR and HER-2 were not detectable in any specimens.

CONCLUSIONS

Our study suggests that ESS is a hormone-dependent malignancy, with hormonal therapy having activity in recurrent disease. Targeted therapy, specifically targeting c-abl may be a potential treatment for this disease.

Role of mucins in the skin during benign and malignant conditions

Skin-related diseases comprise a major health challenge to the practicing physician, and constitute a significant psychological, social and financial burden to the society. Further, skin cancer, especially non-melanoma skin cancer is currently the leading type of malignancy in the Western world. Given the huge burden of skin diseases, there is growing emphasis on understanding their pathophysiology, and towards their early detection. Mucins are high-molecular weight O- and N-linked glycoproteins that have emerged in recent years as important molecules in maintaining health and in promoting or protecting against inflammation and cancer. They have also begun to emerge as highly specific diagnostic and prognostic markers and novel therapeutic targets in several malignant disorders. However, their role in cutaneous pathologies has remained largely obscured. The present review provides the expression patterns and proposed role of mucins in the healthy skin and various benign and malignant skin diseases. The review has immense clinical significance as the availability of highly specific reagents including monoclonal antibodies against mucins makes them extremely attractive targets for specific diagnosis and/or immunotherapy of benign and malignant cutaneous diseases.

GIST with a twist--upregulation of PDGF-B resulting in metachronous gastrointestinal stromal tumor and dermatofibrosarcoma protuberans

CASE REPORT

A 61-year-old male was referred following an incidental radiological discovery of an intra-abdominal mass. His medical history included excision of a lumbar dermatofibrosarcoma protuberans (DFSP) 5 years previously. A CT scan of the abdomen revealed a mass arising from the greater curvature of the stomach. Upper GI endoscopy was normal. He underwent successful laparoscopic resection of this mass.

MATERIALS AND METHODS

The histology of the abdominal mass revealed a gastrointestinal stromal tumor (GIST) with poor prognostic indicators. Immunohistochemical analysis of the GIST and his previous DFSP was performed.

RESULTS

Immunohistochemistry suggested a link between the GIST and his previous DFSP involving the PDGF signalling system.

DISCUSSION

Both GIST and DFSP are extremely rare tumors. A mutation in the platelet-derived growth factor receptor alpha (PDGFR-alpha) has been described in 5-15% of GISTs. It has been shown that DFSP is frequently associated with a translocation between PDGF-B (Chr 22) and COL1A1 (Chr 17), causing continuous activation of PDGFR-beta. Literature review confirms that there are no previously reported cases of both of these tumors occurring in the same patient.

CONCLUSION

We hypothesize that this patient may have a previously undescribed genetic mutation involving the PDGF signalling system, resulting in these two very rare malignancies. Immunohistochemistry studies confirmed the link on this occasion. Improvements in our understanding of the molecular biology of the PDGF system may novel therapeutic targets in the future.

Immunohistochemical Markers of Value in the Diagnosis of Mesenchymal Lesions of the Female Genital Tract

Pure mesenchymal tumors may occur anywhere in the female genital tract, but they are most common in the uterine corpus, leiomyoma being by far the most prevalent. These tumors, and other uncommon mesenchymal lesions within the uterine corpus and elsewhere in the female genital tract, may result in several diagnostic problems. Morphology remains paramount and, in most cases, an unequivocal diagnosis can be made based on examination of the hematoxylin and eosin stained sections, combined with an appreciation of the clinical and gross pathologic features. In difficult cases, immunohistochemistry can significantly contribute to the final diagnosis. In this article, the immunohistochemistry of neoplastic and nonneoplastic mesenchymal lesions of the female genital tract is discussed site by site, concentrating on markers that are of value in diagnosis and in differential diagnosis. The immunophenotype of mixed epithelial and mesenchymal neoplasms and pure epithelial neoplasms with a component of spindle cells is discussed, where appropriate, because these can enter into the differential diagnosis of a pure mesenchymal lesion.

The expression and prognostic significance of platelet-derived growth factor receptor alpha in mature T- and natural killer-cell lymphomas

Platelet-derived growth factor receptor alpha (PDGFRA) is important in numerous malignancies and can serve as a target for therapeutic strategy. We aimed to assess the role of PDGFRA expression in mature T- and natural killer (NK)-cell lymphomas. We used immunohistochemistry to analyze PDGFRA expression in mature T- and NK-cell lymphomas in tissue samples from 50 patients. In positive samples, we then did a mutational analysis of the PDGFRA gene on exons 10, 12, 14, and 18. The relationship between PDGFRA expression and overall survival in mature T- and NK-cell lymphomas was statistically analyzed in the study. We analyzed PDGFRA expression in four subtypes: angioimmunoblastic T-cell lymphoma (3/8, 37.5%); anaplastic large cell lymphoma (5/7, 71.4%); NK/T-cell lymphoma, nasal type (9/12, 75%); and peripheral T-cell lymphoma, unspecified (PTCLu; 7/23, 30.4%). It was lower in PTCLu than in other subtypes (30.4% vs. 63%, p=0.022). PDGFRA expression was not related to PDGFRA gene mutation. Overall survival in mature T- and NK-cell lymphomas correlated significantly with disease subtypes and an international prognostic index but not PDGFRA expression. Our study showed that PDGFRA expression was different in mature T- and NK-cell lymphomas. PDGFRA expression in PTCLu was lower in the present study than in previous reports done in Western countries. It suggests that this disease is biologically distinct in different races (30.4% vs. 91-100%).

Hormonal therapy of endometrial stromal sarcoma

PURPOSE OF REVIEW

Low-grade endometrial stromal sarcomas are steroid receptor positive tumors with slow tumor progression and high recurrence rates, which lack established treatment protocols. We present an update on hormonal therapy options.

RECENT FINDINGS

In the past, hormonal therapy consisted of progestins for advanced/recurrent/metastatic low-grade endometrial stromal sarcomas. Aromatase inhibitors and gonadotropin-releasing hormone analogues have become new effective alternatives for first and second line treatment. The high recurrence rates after short disease free intervals in low-grade endometrial stromal sarcoma patients were partly due to inadvertent growth stimulation during estrogen-containing hormone replacement therapy and tamoxifen treatment, which - according to current knowledge - are contraindicated. Recently, hormonal therapy has been introduced for the prevention of recurrences. Aromatase inhibitors are becoming the treatment of choice, since progestins are poorly tolerated due to side effects. The effective duration of preventive hormonal therapy is still undetermined.

SUMMARY

Hormonal therapy with progestins, aromatase inhibitors and gonadotropin-releasing hormone analogues has become an effective treatment alternative to radiation and chemotherapy for low-grade endometrial stromal sarcoma patients. Preventive hormonal therapy is of particular interest in the setting of concomitant endometriosis.