New molecular targets and biological therapies in sarcomas

Immunotherapy: A New (and Old) Approach to Treatment of Soft Tissue and Bone Sarcomas

Soft tissue and bone sarcomas are a rare and heterogeneous form of cancer. With standard of care treatment options including surgery, radiation, and chemotherapy, the long-term survival is still low for high-risk soft tissue sarcoma patients. New treatment strategies are needed. Immunotherapy offers a new potential treatment paradigm with great promise. Immunotherapy of soft tissue sarcomas dates back to Dr. Coley's first use of toxins in the late 1800s. A variety of strategies of immunotherapy have been tried in soft tissue and bone sarcomas, including various vaccines and cytokines, with limited success. Results of these early clinical trials with vaccines and cytokines were disappointing, but there are reasons to be optimistic. Recent advances, particularly with the use of adoptive T-cell therapy and immune checkpoint inhibitors, have led to a resurgence of this field for all cancer patients. Clinical trials utilizing adoptive T-cell therapy and immune checkpoint inhibitors in soft tissue and bone sarcomas are under way. This paper reviews the current state of evidence for the use of immunotherapy, as well as current immunotherapy strategies (vaccines, adopative T-cell therapy, and immune checkpoint blockade), in soft tissue and bone sarcomas. By understanding the tumor microenviroment of sarcomas and how it relates to their immunoresponsiveness, better immunotherapy clinical trials can be designed, hopefully with improved outcomes for soft tissue and bone sarcoma patients.

IMPLICATIONS FOR PRACTICE

Immunotherapy is a promising treatment paradigm that is gaining acceptance for the management of several cancers, including melanoma, renal cell carcinoma, prostate cancer, and lung cancer. There is a long history of immunotherapy in the treatment of soft tissue and bone sarcomas, although with little success. It is important to understand past failures to develop future immunotherapy treatment strategies with an improved possibility of success. This article reviews the history of and current state of immunotherapy research in the treatment of soft tissue and bone sarcomas, with particular regard to vaccine trials, adoptive T-cell therapy, and immune checkpoint blockade.

Gene translocations in musculoskeletal neoplasms

Establishing the best diagnosis for musculoskeletal neoplasms requires a multidisciplinary approach using clinical, radiographic, and histologic analyses. Despite this rigorous approach, establishing accurate diagnoses and prognoses remains challenging. Improved diagnostic methods are expected as unique molecular signals for specific bone and soft tissue cancers are identified. We performed a systematic review of the best available evidence to explore three major applications of molecular genetics that will best benefit clinical management of musculoskeletal neoplasms: diagnostic, prognostic, and therapeutic applications. The specific questions addressed in this systematic review are: (1) What sets of histopathologic sarcoma subtypes will benefit from molecular evaluation and diagnosis? (2) What molecular methods are best applied to histopathologic sarcomas to distinguish between major subtypes? (3) How do the molecular patterns discovered on genetic diagnosis affect prognosis of certain sarcomas? (4) Which sarcoma translocations can benefit from an improved response and outcome using existing and forthcoming pharmacogenetic approaches targeting molecular events? This review summarizes recent advances in molecular genetics that are available and will soon be available to clinicians to better predict outcomes and subsequently help make future treatment decisions.

LEVEL OF EVIDENCE

Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Molecular Imaging: Integration of Molecular Imaging into the Musculoskeletal Imaging Practice

Chronic musculoskeletal diseases such as arthritis, malignancy, and chronic injury and/or inflammation, all of which may produce chronic musculoskeletal pain, often pose challenges for current clinical imaging methods. The ability to distinguish an acute flare from chronic changes in rheumatoid arthritis, to survey early articular cartilage breakdown, to distinguish sarcomatous recurrence from posttherapeutic inflammation, and to directly identify generators of chronic pain are a few examples of current diagnostic limitations. There is hope that a growing field known as molecular imaging will provide solutions to these diagnostic puzzles. These techniques aim to depict, noninvasively, specific abnormal cellular, molecular, and physiologic events associated with these and other diseases. For example, the presence and mobilization of specific cell populations can be monitored with molecular imaging. Cellular metabolism, stress, and apoptosis can also be followed. Furthermore, disease-specific molecules can be targeted, and particular gene-related events can be assayed in living subjects. Relatively recent molecular and cellular imaging protocols confirm important advances in imaging technology, engineering, chemistry, molecular biology, and genetics that have coalesced into a multidisciplinary and multimodality effort. Molecular probes are currently being developed not only for radionuclide-based techniques but also for magnetic resonance (MR) imaging, MR spectroscopy, ultrasonography, and the emerging field of optical imaging. Furthermore, molecular imaging is facilitating the development of molecular therapies and gene therapy, because molecular imaging makes it possible to noninvasively track and monitor targeted molecular therapies. Implementation of molecular imaging procedures will be essential to a clinical imaging practice. With this in mind, the goal of the following discussion is to promote a better understanding of how such procedures may help address specific musculoskeletal issues, both now and in the years ahead.

Cytogenetic alterations in nonmelanoma skin cancer: a review

Since the advent of cytogenetic analysis, knowledge about fundamental aspects of cancer biology has increased, allowing the processes of cancer development and progression to be more fully understood and appreciated. Classical cytogenetic analysis of solid tumors had been considered difficult, but new advances in culturing techniques and the addition of new cytogenetic technologies have enabled a more comprehensive analysis of chromosomal aberrations associated with solid tumors. Our purpose in this review is to discuss the cytogenetic findings on a number of nonmelanoma skin cancers, including squamous- and basal cell carcinomas, keratoacanthoma, squamous cell carcinoma in situ (Bowen's disease), and solar keratosis. Through classical cytogenetic techniques, as well as fluorescence-based techniques such as fluorescence in situ hybridization and comparative genomic hybridization, numerous chromosomal alterations have been identified. These aberrations may aid in further defining the stages and classifications of nonmelanoma skin cancer and also may implicate chromosomal regions involved in progression and metastatic potential. This information, along with the development of newer technologies (including laser capture microdissection and comparative genomic hybridization arrays) that allow for more refined analysis, will continue to increase our knowledge about the role of chromosomal events at all stages of cancer development and progression and, more specifically, about how they are associated with nonmelanoma skin cancer.

Prognostic Significance of Allelic Imbalance at the c-kit Gene Locus and c-kit Overexpression by Immunohistochemistry in Pediatric Osteosarcomas

Purpose

Since the recent development of biologic agents targeting oncogenes, increasing attention has been focused on determining the role of tyrosine kinase receptors in the pathogenesis of tumors. Our study was designed to investigate the status of region 4q12, which contains the candidate gene c-kit, and the expression of c-kit by immunohistochemistry (IHC).

Patients and Methods

Paired blood and biopsy specimens of 68 children treated for high-grade primary osteosarcomas were collected. Microsatellite analysis at two genomic sites containing c-kit gene was performed on paired DNA using a sensible fluorescent polymerase chain reaction technology. To confirm the DNA data, we studied c-kit protein expression by IHC in 56 available paraffin-embedded tumor tissues.

Results

The frequency of allelic imbalance (AI) at locus 4q12 was 39% in the overall population. In agreement with previous studies, we did not detect microsatellite instability, allowing us to hypothesize that this pathway is not implicated. Furthermore, the normal status at locus 4q12 was associated with a significantly better survival in the whole osteosarcoma population (P = .05). IHC overexpression of c-kit was concordant in all cases presenting an AI. However, normal status at locus 4q12 was correlated to an absence of c-kit protein expression in 19 (65.5%) of 29 informative cases.

Conclusion

Allelotyping of locus 4q12, which contains the c-kit gene, could help pediatric osteosarcoma prognostic screening and showed a strong correlation with overexpression of c-kit protein. These results allowed us to hypothesize that, in some cases, a mutation of c-kit gene could lead to a protein overexpression.

Sarcomes du grêle

Sarcomas of the small intestine are rare, clearly differentiated, malignant, mesenchymatous tumours that can be of smooth muscle, Schwann cell or fibroblastic origin. From a clinical point of view, the pain and abdominal mass are the 2 types of symptoms that frequently reveal the disease. In rare cases, sarcomas of the small intestine are manifested by an acute complication. No imaging method can clearly confirm the diagnosis. Before immunohistochemistry, differential diagnosis was made on undifferentiated mesenchymatous "stromal" tumours, which are also rare. Exeresis must be complete and without perforation of the tumour because of the risk of locoregional relapse. The benefits provided by chemotherapy and radiotherapy are limited because of the low mitotic activity of the tumour cells and its weak vascularisation. Long-term survival is limited by poor prognosis criteria: high grade malignancy, size greater than 5 cm, tumour extension, perforation of the tumour, quality of surgical resection and histological type.

Expression of matrix metalloproteinase-9 correlates with poor prognosis in human malignant fibrous histiocytoma

PURPOSE

92 kDa matrix metalloproteinase-9 (MMP-9) is believed to play an important role in degrading the matrix and basement membrane, contributing to the invasion and metastasis of malignant solid tumors. However, little is known about its involvement in a malignant fibrous histiocytoma. The aim of this study was to investigate the expression of MMP-9 and to correlate its expression with clinicopathologic parameters in human malignant fibrous histiocytomas.

MATERIALS AND METHODS

Archival tumor tissues from 20 patients with a malignant fibrous histiocytoma were analyzed by immunohistochemistry for the expression of MMP-9. Clinical information was obtained through the computerized retrospective database from the tumor registry.

RESULTS

Seventeen of 20 (85%) tumors showed a positive reaction for MMP-9. MMP-9 activity was inversely correlated with patients' survival time (p=.011). There was no significant correlation between the activated MMP-9 expression and all the other clinicopathologic variables.

CONCLUSION

Our data demonstrate that MMP-9 activation is likely to occur in human malignant fibrous histiocytomas. It is also noteworthy that the expression of MMP-9 may aid in predicting patients' poor prognosis.

Molecular genetics of pediatric soft tissue tumors: clinical application

The application of molecular genetics to pediatric soft tissue tumors has grown tremendously over the last decade. It has resulted in the identification of novel genes that have provided us with an increased understanding of oncogenesis. Furthermore, these findings have identified diagnostic and potentially prognostic factors for patient management. Molecular diagnostic techniques, such as reverse transcription PCR (RT-PCR) and fluorescence in situ hybridization (FISH), have become important tools for evaluating pediatric soft tissue tumors. By detecting characteristic fusion genes, these techniques have greatly increased the diagnostic accuracy of histopathological classification. One of the exciting promises of the development of these molecular techniques is their ability to detect micrometastasis and minimal residual disease. Monitoring of minimal residual disease in pediatric soft tissue tumors by quantitative RT-PCR may provide important prognostic information. Furthermore, the potential development of targeted therapy based on the understanding of the molecular pathology of a specific soft tissue tumor may complement existing treatments and improve disease outcome.

Capillary electrophoresis and its application in the clinical laboratory

Over the past 10 years, capillary electrophoresis (CE) is an analytical tool that has shown great promise in replacing many conventional clinical laboratory methods, especially electrophoresis and high performance liquid chromatography (HPLC). The main attraction of CE was that it was fast, used small amounts of sample and reagents, and was extremely versatile, being able to separate large and small analytes, both neutral and charged. Because of this versatility, numerous methods for clinically relevant analytes have been developed. However, with the exception of the molecular diagnostic and forensic laboratories CE has not had a major impact. A possible reason is that CE is still perceived as requiring above-average technical expertise, precluding its use in a laboratory workforce that is less technically adept. With the introduction of multicapillary instruments that are more automated, less technique-dependent, in addition to the availability of commercial and cost effective test kit methods, CE may yet be accepted as a instrument routinely used in the clinical laboratories. Thus, this review will focus on the areas where CE shows the most potential to have the greatest impact on the clinical laboratory. These include analysis of proteins found in serum, urine, CSF and body fluids, immunosubstraction electrophoresis, hemoglobin variants, lipoproteins, carbohydrate-deficient transferrin (CDT), forensic and therapeutic drug screening, and molecular diagnostics.

Photochemical Internalization Enhances the Cytotoxic Effect of the Protein Toxin Gelonin and Transgene Expression in Sarcoma Cells¶

Further advantages in the treatment of soft-tissue sarcomas will only be achieved by tailoring the adjuvant therapy after surgery. The photochemically directed release of macro-molecules from endosomes and lysosomes into the cytosol is a novel technology, named photochemical internalization (PCI), that has been evaluated for treatment of sarcoma cells in vitro. Two human synovial sarcoma cell lines (SW 982 and CME-1) were treated with the photosensitizer meso-tetraphenylporphine with two sulfonate groups on adjacent phenyl rings (TPPS2a) and a plasmid encoding enhanced green fluorescent protein (EGFP) complexed to poly-L-lysine to investigate the influence of PCI on gene transfer and with 5 micrograms/mL gelonin to investigate PCI of a Type-I ribosome-inactivating protein toxin. In addition, both cell lines were transduced with an Adenovirus serotype 5 encoding the Escherichia coli lacZ gene (AdHCMV-lacZ, expressing beta-galactosidase) and treated with TPPS2a and light to evaluate the effect of PCI on the transduction rate. Photochemically induced transfection with the reporter gene EGFP in CME-1 cells increased from 0% of cells at no light to 40% of the cells after 60 s of light exposure. In contrast, the SW 982 cells showed no enhanced expression of the gene. The fraction of virally transduced cells was about doubled in both cell lines by means of PCI, although the transduction was more efficient in the CME-1 cells. Both cell lines became up to four-fold more sensitive to light when combining photochemical treatment with gelonin incubation. Our experiments showed that PCI induced the endocytic escape of therapeutic substances in cells derived from human soft-tissue sarcomas.

Mechanisms and future directions for angiogenesis-based cancer therapies

Targeting angiogenesis represents a new strategy for the development of anticancer therapies. New targets derived from proliferating endothelial cells may be useful in developing anticancer drugs that prolong or stabilize the progression of tumors with minimal systemic toxicities. These drugs may also be used as novel imaging and radiommunotherapeutic agents in cancer therapy. In this review, the mechanisms and control of angiogenesis are discussed. Genetic and proteomic approaches to defining new potential targets on tumor vasculature are then summarized, followed by discussion of possible antiangiogenic treatments that may be derived from these targets and current clinical trials. Such strategies involve the use of endogenous antiangiogenic agents, chemotherapy, gene therapy, antiangiogenic radioligands, immunotherapy, and endothelial cell-based therapies. The potential biologic end points, toxicities, and resistance mechanisms to antiangiogenic agents must be considered as these therapies enter clinical trials.