Expression of cancer-testis antigens MAGEA1, MAGEA3, ACRBP, PRAME, SSX2, and CTAG2 in myxoid and round cell liposarcoma

Expression of Cancer-Testis Antigens MAGE-A1, MAGE-A4, NY-ESO-1 and PRAME in Bone and Soft Tissue Sarcomas: The Experience From a Single Center in China

OBJECTIVE

Sarcomas are a heterogeneous group of malignancies, low disease-control levels and the limited durability of responses have prompted the exploration of various novel immunotherapeutic approaches. To preliminarily explore the feasibility of cancer vaccines based on cancer testis antigen in the immunotherapy of sarcomas, we investigate the expression of Cancer/Testis Antigens (CTA) MAGE-A4, PRAME, MAGE-A1, KK-LC-1, and NY-ESO-1 in bone and soft tissue sarcomas, with the aim of assessing their potential for use in sarcoma immunotherapy and determining their expression levels in different subtypes.

METHODS AND RESULTS

We employed immunohistochemistry and multiplex immunostaining microarrays (MI chips) to assess the expression of MAGE-A4, PRAME, MAGE-A1, KK-LC-1, and NY-ESO-1 in 21 cases of undifferentiated pleomorphic sarcoma (UPS), 26 cases of smooth muscle sarcoma, 28 cases of liposarcoma, 40 cases of osteosarcoma (OS), and 13 cases of chondrosarcoma. MAGE-A1 showed the highest expression in osteosarcoma (32.50%), while it was lower in liposarcoma and undifferentiated pleomorphic sarcoma (10.71% and 10.00%) and undetectable in chondrosarcoma. MAGE-A4 expression was elevated in osteosarcoma and undifferentiated pleomorphic sarcoma (40.00% and 33.00%), but lower in liposarcoma and smooth muscle sarcoma (17.00% and 33.00%). NY-ESO-1 expression was relatively low across all sarcoma subtypes. PRAME expression was highest in undifferentiated pleomorphic sarcoma (47.62%) and low in chondrosarcoma (7.69%). None of the sarcomas expressed KK-LC-1. Additionally, while there was no statistically significant correlation between CTA expression and patient age or gender, some differences related to age and gender were observed.

CONCLUSIONS

CTA expression in bone and soft tissue sarcomas was correlated with both CTA type and sarcoma subtype, showing relatively high levels of expression in undifferentiated pleomorphic sarcoma (UPS) and osteosarcoma (OS). The poly-expression of MAGE-A4, PRAME, and MAGE-A1 across all subtypes suggests that these antigens may serve as potential targets for sarcoma-specific immunotherapy.

Molecular genomic insights into melanoma associated proteins PRAME and BAP1

Melanoma, a globally prevalent skin cancer with over 325,000 new cases annually, necessitates a comprehensive under- standing of its molecular components. This study looks at the PRAME (cutaneous melanoma-associated antigen) and BAP1 (gene controlling gene-environment interactions) proteins. Both PRAME and BAP1 are associated with critical genomic alterations that significantly influence melanoma progression and patient outcomes. PRAME is overexpressed in various cancers, especially uveal melanoma (UM), where high levels correlate with poor prognosis and genomic instability linked to chromosome 8q12 alterations. Meanwhile, mutations in BAP1 contribute to increased genomic instability and a higher risk of metastasis in UM, highlighting its importance as a key prognostic marker in tumorigenesis. Established approaches along with features proposed in this work are used to investigate sequence conservation, polyglutamic acid presence, intrinsic disorder of proteins, polar-nonpolar residues arrangement PRAME and BAP1 conserved residues highlight their critical roles in protein function and interaction. Sequence invariance indicates the possibility of functional relevance and evolutionary conservation. PRAME has enhanced intrinsic disorder and flexibility, whereas BAP1 has changed disorder-promoting residue sequences. Polyglutamic acid strings are found in both proteins, emphasizing their modulatory involvement in protein interactions. The ratios and spatial arrangement of amino acids have a profound influence on interactions and gene dysregulation. This work contributes to a better knowledge of the two melanoma-associated proteins viz. PRAME and BAP1 by unraveling their structural and functional complexities.

Novel Therapeutics in Soft Tissue Sarcoma

There has been noteworthy progress in molecular characterisation and therapeutics in soft tissue sarcomas. Novel agents have gained regulatory approval by the FDA. Examples are the tyrosine kinase inhibitors avapritinib and ripretinib in gastrointestinal stromal tumours (GIST), the immune check point inhibitor atezolizumab in alveolar soft part tissue sarcoma, the γ-secretase inhibitor nirogacestat in desmoid tumours, the NTRK inhibitors larotrectinib and entrectinib in tumours with NTRK fusions, the mTOR inhibitor nab-sirolimus in PEComa, and the EZH-2 inhibitor tazemetostat in epithelioid sarcoma. The FDA has also recently granted accelerated approval for autologous T-cell therapy with afami-cel in patients with HLA-A*02 and MAGE-A4-expressing synovial sarcoma. There are other promising treatments that are still investigational, such as MDM2 and CDK4/6 inhibitors in well-/dedifferentiated liposarcoma, immune checkpoint inhibitors in the head and neck angiosarcoma and a subset of patients with undifferentiated pleomorphic sarcoma, and PARP inhibitors in leiomyosarcoma. The challenges in drug development in soft tissue sarcoma are due to the rarity and the molecular heterogeneity of the disease and the fact that many subtypes are associated with complex karyotypes or non-targetable molecular alterations. We believe that progress maybe possible with a better understanding of the complex biology, the development of novel compounds for difficult targets such as proteolysis targeting chimeras (Protacs), the utilisation of modern clinical trial designs, and enhanced collaboration of academia with industry to develop treatments with a strong biologic rationale.

PRAME Staining of Adnexal Lesions and Common Skin Cancer Types: Biomarker with Potential Diagnostic Utility

PRAME (PReferentially expressed Antigen in MElanoma) is a tumor-associated antigen first identified in tumor-reactive T-cell clones derived from a patient with metastatic melanoma. Immunohistochemistry (IHC) for PRAME is useful for diagnostic purposes to support a suspected diagnosis of melanoma. Anecdotally, PRAME has been observed to stain sebaceous units in glands in background skin. We examined the expression of PRAME in adnexal lesions and common skin cancers to determine whether it is of potential diagnostic utility in supporting the differentiation between sebaceous and non-sebaceous lesions. IRB approval from Mount Sinai Medical Center (MSMC) was obtained. This is a single-center retrospective cohort analysis over a ten-year period (1 January 2012, and 31 December 2023). We used the pathological database of skin lesions, including sebaceous, sweat gland, and follicular lesions, in addition to basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), from 81 patients who underwent shave/punch biopsies or surgical excisions. We evaluated the IHC staining percentage positivity and intensity for PRAME. Staining intensity was subcategorized into negative, weak, moderate, and strong, whereas expression percentage positivity was subcategorized into 0%, 1-25%, 26-50%, 51-75%, and 76-100%. Most sebaceous versus non-sebaceous lesions exhibited cytoplasmic staining of moderate to strong intensity in >75% of cells. PRAME has a sensitivity and specificity of 100.0% and 86.7%, respectively, to support distinguishing between sebaceous and non-sebaceous adnexal lesions (regardless of whether they are benign or malignant). BCCs and SCCs showed weak to moderate nuclear staining for PRAME in >75% of cells. None of the 13 lesions of hair follicle origin showed any staining. A total of 26 of the 32 lesions of sweat gland origin were negative while 6 (18.75%) showed positive staining. In conclusion, we confirm the potential utility of PRAME for supporting the distinction between sebaceous and non-sebaceous adnexal lesions on one hand, and on the other, distinguishing BCC and SCC that may show nuclear staining from sebaceous carcinoma that shows cytoplasmic staining.

An overview on liposarcoma subtypes: Genetic alterations and recent advances in therapeutic strategies

Liposarcoma (LPS) is a rare malignancy of adipocytic differentiation. According to World Health Organization classification, LPS comprises of four principle subtypes Atypical lipomatous tumor/Well-differentiated liposarcoma (ATL/WDLPS), Dedifferentiated liposarcoma (WDLPS), Myxoid liposarcoma (MLPS), and Pleomorphic liposarcoma (PLPS). Each subtype can develop at any location and shows distinct clinical behavior and treatment sensitivity. ATL/ WDLPS subtype has a higher incidence rate, low recurrence, and is insensitive to radiation and chemotherapy. DDLPS is the focal progression of WDLPS, which is aggressive and highly metastasizing. MLPS is sensitive to radiation and chemotherapy, with a higher recurrence rate and metastasis. PLPS subtype is highly metastasizing, has a poor prognosis, and exhibiting higher recurrence rate. Initial histological analysis provides information for the characterization of LPS subtypes', further molecular and genetic analysis provides certain subtype specifications, such as gene amplifications and gene fusions. Such molecular genetic alterations will be useful as therapeutic targets in various cancers, including the LPS subtypes. A wide range of novel therapeutic agents based on genetic alterations that aim to target LPS subtypes specifically are under investigation. This review summarizes the LPS subtype classification, their molecular genetic characteristics, and the implications of genetic alterations in therapeutics.

PReferentially Expressed Antigen in MElanoma Expression in Uterine and Ovarian Carcinosarcomas

Carcinosarcoma (CS) is an aggressive form of gynecologic malignancy that accounts for ~5% of carcinomas in the endometrium and ovaries. There has been no significant improvement in survival over the last decades despite additional treatment options. PReferentially Expressed Antigen in MElanoma (PRAME) is an immunotherapy target used for the treatment of several solid tumors. We explored the PRAME protein expression levels in ovarian and uterine CS (n = 29). The expression levels were recorded by H-score (percentage of positively stained cells multiplied by staining intensity) in carcinomatous and sarcomatous components separately and compared by paired t-test. The marker expression levels of ovarian and uterine CS were tested against each other in the CS group. Sarcoma-predominant samples (>50% of the sampled tissue) were compared with samples without predominant sarcomatous components by a 2-sample pooled t-test. In addition, high-grade carcinomatous components of CS samples were tested against low-grade endometrioid carcinoma (International Federation of Gynecology and Obstetrics grades 1 and 2; n = 13), and sarcomatous components against uterine leiomyosarcoma (n = 14). There was no significant difference between any subgroups except for sarcomatous elements of CS and leiomyosarcoma ( P < 0.001). A weak positive correlation was found between H-scores of carcinomatous and sarcomatous components ( P = 0.062, r = 0.36). In the ovarian CS group, there was a moderate inverse correlation between age and the mean H-score of the carcinomatous component ( r = -0.683, P = 0.02). Our results further support PRAME overexpression in gynecologic cancers, including CS with similar expression levels in epithelial and mesenchymal components. PRAME might have a role in epithelial-mesenchymal transition in this group of cancers.

Spitz Melanocytic Tumors: A Fascinating 75-Year Journey

Over the last 75 years, our understanding of Spitz lesions has undergone substantial evolution. Initially considered a specific type of melanoma, the perception has shifted towards recognizing Spitz lesions as a spectrum comprising Spitz nevi, Spitz melanocytomas, and Spitz melanomas. Spitz lesions are known for posing a significant diagnostic challenge regarding the distinction between benign neoplasms displaying atypical traits and melanomas. A comprehensive understanding of their molecular basis and genomic aberrations has significantly improved precision in classifying and diagnosing these challenging lesions. The primary aim of this review is to encapsulate the current understanding of the molecular pathogenesis and distinct clinicopathologic characteristics defining this intriguing set of tumors.

Genetic, Epigenetic and Transcriptome Alterations in Liposarcoma for Target Therapy Selection

Liposarcoma (LPS) is one of the most common adult soft-tissue sarcomas (STS), characterized by a high diversity of histopathological features as well as to a lesser extent by a spectrum of molecular abnormalities. Current targeted therapies for STS do not include a wide range of drugs and surgical resection is the mainstay of treatment for localized disease in all subtypes, while many LPS patients initially present with or ultimately progress to advanced disease that is either unresectable, metastatic or both. The understanding of the molecular characteristics of liposarcoma subtypes is becoming an important option for the detection of new potential targets and development novel, biology-driven therapies for this disease. Innovative therapies have been introduced and they are currently part of preclinical and clinical studies. In this review, we provide an analysis of the molecular genetics of liposarcoma followed by a discussion of the specific epigenetic changes in these malignancies. Then, we summarize the peculiarities of the key signaling cascades involved in the pathogenesis of the disease and possible novel therapeutic approaches based on a better understanding of subtype-specific disease biology. Although heterogeneity in liposarcoma genetics and phenotype as well as the associated development of resistance to therapy make difficult the introduction of novel therapeutic targets into the clinic, recently a number of targeted therapy drugs were proposed for LPS treatment. The most promising results were shown for CDK4/6 and MDM2 inhibitors as well as for the multi-kinase inhibitors anlotinib and sunitinib.

PDE3A Is a Highly Expressed Therapy Target in Myxoid Liposarcoma

Liposarcomas (LPSs) are a heterogeneous group of malignancies that arise from adipose tissue. Although LPSs are among the most common soft-tissue sarcoma subtypes, precision medicine treatments are not currently available. To discover LPS-subtype-specific therapy targets, we investigated RNA sequenced transcriptomes of 131 clinical LPS tissue samples and compared the data with a transcriptome database that contained 20,218 samples from 95 healthy tissues and 106 cancerous tissue types. The identified genes were referred to the NCATS BioPlanet library with Enrichr to analyze upregulated signaling pathways. PDE3A protein expression was investigated with immunohistochemistry in 181 LPS samples, and PDE3A and SLFN12 mRNA expression with RT-qPCR were investigated in 63 LPS samples. Immunoblotting and cell viability assays were used to study LPS cell lines and their sensitivity to PDE3A modulators. We identified 97, 247, and 37 subtype-specific, highly expressed genes in dedifferentiated, myxoid, and pleomorphic LPS subtypes, respectively. Signaling pathway analysis revealed a highly activated hedgehog signaling pathway in dedifferentiated LPS, phospholipase c mediated cascade and insulin signaling in myxoid LPS, and pathways associated with cell proliferation in pleomorphic LPS. We discovered a strong association between high PDE3A expression and myxoid LPS, particularly in high-grade tumors. Moreover, myxoid LPS samples showed elevated expression levels of SLFN12 mRNA. In addition, PDE3A- and SLFN12-coexpressing LPS cell lines SA4 and GOT3 were sensitive to PDE3A modulators. Our results indicate that PDE3A modulators are promising drugs to treat myxoid LPS. Further studies are required to develop these drugs for clinical use.

Cutaneous Melanoma: A Review of Multifactorial Pathogenesis, Immunohistochemistry, and Emerging Biomarkers for Early Detection and Management

Cutaneous melanoma (CM) is an increasingly significant public health concern. Due to alarming mortality rates and escalating incidence, it is crucial to understand its etiology and identify emerging biomarkers for improved diagnosis and treatment strategies. This review aims to provide a comprehensive overview of the multifactorial etiology of CM, underscore the importance of early detection, discuss the molecular mechanisms behind melanoma development and progression, and shed light on the role of the potential biomarkers in diagnosis and treatment. The pathogenesis of CM involves a complex interplay of genetic predispositions and environmental exposures, ultraviolet radiation exposure being the predominant environmental risk factor. The emergence of new biomarkers, such as novel immunohistochemical markers, gene mutation analysis, microRNA, and exosome protein expressions, holds promise for improved early detection, and prognostic and personalized therapeutic strategies.

Immunohistochemistry for PRAME in Dermatopathology

ABSTRACT

Preferentially expressed antigen in melanoma (PRAME) is a tumor-associated antigen first identified in a melanoma patient and found to be expressed in most melanomas as well as in variable levels in other malignant neoplasms of epithelial, mesenchymal, or hematolymphoid lineage. Detection of PRAME expression in formalin-fixed paraffin-embedded tissue is possible by immunohistochemistry (IHC) with commercially available monoclonal antibodies. In situ and invasive melanoma frequently show a diffuse pattern of nuclear PRAME immunoreactivity which contrasts with the infrequent and typically nondiffuse staining seen in nevi. In many challenging melanocytic tumors, results of PRAME IHC and other ancillary tests correlate well, but not always: The tests are not interchangeable. Most metastatic melanomas are positive for PRAME, whereas nodal nevi are not. Numerous studies on PRAME IHC have become available in the past few years with results supporting the value of PRAME IHC as an ancillary tool in the evaluation of melanocytic lesions and providing insights into limitations in sensitivity and specificity as well as possible pitfalls that need to be kept in mind by practicing pathologists.

PRAME expression in 137 primary cutaneous melanomas and comparison with 38 related metastases

Melanocytic lesions have always represented a diagnostic challenge for surgical pathologists. According to the literature, PRAME showed great promise as an immunohistochemical tool in the distinction between benign and malignant melanocytic lesions. In the present study, we retrospectively analyzed 137 thicker (Breslow > 1 mm) primary cutaneous melanomas with the aim to better understand the utility of PRAME immunohistochemistry in daily practice and also to investigate if PRAME could represent a prognostic biomarker for cutaneous melanomas. PRAME immunohistochemistry was performed in all melanomas and in the metastases with antibodies to PRAME (dilution 1:1000, clone Ab219650) on an automated immunostainer (Ventana Benchmark Ultra) using a brown chromogen (DAB). We found that melanomas (59.1%) show diffuse PRAME expression (score 4 +). 99 (72.3%) primary cutaneous melanoma had no relapse during the follow-up. Of this group of melanomas, 61/99 (61.6%) were diffusely positive for PRAME. 38 (27.7%) primary cutaneous melanoma had relapses. Of this group, 28/36 (77.7%) were diffusely positive. We did not find any statistical correlation between diffuse PRAME expression and the presence of driver mutation in BRAF gene (p = 0.927), NRAS gene (p = 0.496) or either of the two (p = 0.138). We did not find a prognostic significance of diffuse PRAME expression for relapse (p = 0.462) or survival rate (p = 0.245). The prognostic value of PRAME has been only reported in mucosal, uveal and cutaneous thin melanomas. Here, we show statistical analyses on PRAME expression for melanoma with Breslow > 1 mm based on survival rate and long-term follow-up. According to our results, PRAME is a useful immunohistochemical ancillary tool in daily practice diagnosis of melanocytic lesions.

Sarcoma Immunotherapy: Confronting Present Hurdles and Unveiling Upcoming Opportunities

Sarcomas are rare and heterogeneous mesenchymal neoplasms originating from the bone or soft tissues, which pose significant treatment challenges. The current standard treatment for sarcomas consists of surgical resection, often combined with chemo- and radiotherapy; however, local recurrence and metastasis remain significant concerns. Although immunotherapy has demonstrated promise in improving long-term survival rates for certain cancers, sarcomas are generally considered to be relatively less immunogenic than other tumors, presenting substantial challenges for effective immunotherapy. In this review, we examine the possible opportunities for sarcoma immunotherapy, noting cancer testis antigens expressed in sarcomas. We then cover the current status of immunotherapies in sarcomas, including progress in cancer vaccines, immune checkpoint inhibitors, and adoptive cellular therapy and their potential in combating these tumors. Furthermore, we discuss the limitations of immunotherapies in sarcomas, including a low tumor mutation burden and immunosuppressive tumor microenvironment, and explore potential strategies to tackle the immunosuppressive barriers in therapeutic interventions, shedding light on the development of effective and personalized treatments for sarcomas. Overall, this review provides a comprehensive overview of the current status and potential of immunotherapies in sarcoma treatment, highlighting the challenges and opportunities for developing effective therapies to improve the outcomes of patients with these rare malignancies.

Potential diagnostic utility of PRAME and p16 immunohistochemistry in melanocytic nevi and malignant melanoma

BACKGROUND

PRAME (PReferentially expressed Antigen in MElanoma) is a tumor-associated antigen that has been studied in various cutaneous melanocytic lesions. p16, on the other hand, has been proposed to aid in distinguishing between benign and malignant melanocytic neoplasms. Studies on the diagnostic utility of PRAME and p16 in combination in differentiating nevi from melanoma are limited. We aimed to assess the diagnostic utility of PRAME and p16 in melanocytic tumors and their role in distinguishing between malignant melanomas and melanocytic nevi.

METHODS

This is a single-center retrospective cohort analysis over a 4-year period (2017-2020). We used the pathological database of malignant melanomas (77 cases) and melanocytic nevi (51 cases) specimens from patients who underwent shave/punch biopsies or surgical excisions and evaluated immunohistochemical staining percentage positivity and intensity for PRAME and p16.

RESULTS

Most malignant melanomas showed positive/diffuse PRAME expression (89.6%); on the other hand, 96.1% of nevi did not express PRAME diffusely. p16 was expressed consistently in nevi (98.0%). However, p16 expression in malignant melanoma was infrequent in our study. PRAME had a sensitivity and specificity of 89.6% and 96.1%, respectively, for melanomas versus nevi; on the other hand, p16 had a sensitivity and specificity of 98.0% and 28.6%, respectively, for nevi versus melanoma. Also, a PRAME+/p16- melanocytic lesion is unlikely to be a nevus where most nevi were PRAME-/p16+.

CONCLUSION

In conclusion, we confirm the potential utility of PRAME and p16 for distinguishing melanocytic nevi from malignant melanomas.

Cancer-Associated B Cells in Sarcoma

Despite being one of the first types of cancers studied that hinted at a major role of the immune system in pro- and anti-tumor biology, little is known about the immune microenvironment in sarcoma. Few types of sarcoma have shown major responses to immunotherapy, and its rarity and heterogeneity makes it challenging to study. With limited systemic treatment options, further understanding of the underlying mechanisms in sarcoma immunity may prove crucial in advancing sarcoma care. While great strides have been made in the field of immunotherapy over the last few decades, most of these efforts have focused on harnessing the T cell response, with little attention on the role B cells may play in the tumor microenvironment. A growing body of evidence suggests that B cells have both pro- and anti-tumoral effects in a large variety of cancers, and in the age of bioinformatics and multi-omic analysis, the complexity of the humoral response is just being appreciated. This review explores what is currently known about the role of B cells in sarcoma, including understanding the various B cell populations associated with sarcoma, the organization of intra-tumoral B cells in tertiary lymphoid structures, recent trials in immunotherapy in sarcoma, intra-tumoral immunoglobulin, the pro-tumor effects of B cells, and exciting future areas for research.

PRAME is a useful marker for the differential diagnosis of melanocytic tumours and histological mimics

AIMS

Although the morphological assessment of melanoma is generally straightforward, diagnosis can be especially difficult when the significant morphological and immunohistochemical results overlap with those of benign and malignant melanocytic tumours and histological mimics. This study assessed the potential diagnostic utility of measuring PReferentially expressed Antigen in MElanoma (PRAME) immunohistochemically in naevi, melanomas and clear cell sarcomas (CCSs) in Chinese patients.

METHODS

We examined the immunohistochemical expression of PRAME in 317 melanocytic naevi, 178 primary melanomas, 72 metastatic melanomas and 19 CCSs and compared the sensitivity and specificity of PRAME immunohistochemistry (IHC) in the differential diagnosis of melanocytic tumours and histological mimics.

RESULTS

Of the 317 melanocytic naevi, 98.1%were completely negative for PRAME; six cases showed focal PRAME immunoreactivity in a minor population of lesional melanocytes. Diffuse nuclear immunoreactivity for PRAME was found in 89.9% of primary melanomas and 93.1% of metastatic melanomas. Regarding melanoma subtypes, PRAME was expressed in 100% of superficial spreading melanomas, 100% of melanomas arise in congenital naevus, 91.4% of nodular melanomas, 87.8% of acral lentigo melanomas, 80.0% of lentigo malignant melanomas, 60.0% of Spitz melanomas, 96.2% of mucosal melanomas and 80.0% of uveal melanomas. None of the two desmoplastic melanomas expressed PRAME. Of the 19 CCS cases, 89.5% were negative for PRAME and 10.5% showed focal weak PRAME immunoreactivity in a minor population of tumour cells.

CONCLUSIONS

Our findings indicate that PRAME may be a useful marker to support a suspected diagnosis of melanoma. In addition, lack of PRAME expression is a valuable hint to CCS in a suspected case, and then molecular confirmation of the presence of EWSR1 rearrangement is necessary.

PRAME expression in spindle cell melanoma, malignant peripheral nerve sheath tumour, and other cutaneous sarcomatoid neoplasms: a comparative analysis

Diagnosis of spindle cell/sarcomatoid melanoma may be challenging due to frequent loss of expression of melanocytic marker(s) and histomorphologic resemblance to various mesenchymal tumours, particularly malignant peripheral nerve sheath tumour (MPNST). Overexpression of PReferentially expressed Antigen in MElanoma (PRAME) supports a diagnosis of melanoma when evaluating challenging melanocytic tumours. PRAME expression in MPNST and other cutaneous sarcomatoid neoplasms, however, has not been well characterised. We aimed to determine the utility of PRAME immunostain in distinguishing spindle cell melanoma from MPNST and other sarcomatoid mimics. PRAME expression was scored by extent (0 to 4+) and intensity (0 to 3) of staining. A strong positive correlation was observed between the extent and intensity scores (r = 0.84). An extent score of 4+, defined by staining in 76-100% of tumour cells, was seen in 56% (23/41) of spindle cell melanomas, 18% (7/38) of MPNSTs, 15% (4/27) of cutaneous sarcomatoid squamous cell carcinomas (SCCs), 33% (5/15) of poorly differentiated cutaneous angiosarcomas, 12% (4/33) of atypical fibroxanthomas (AFXs), 4% (1/25) of pleomorphic dermal sarcomas (PDSs), and none (0/16) of the high-grade cutaneous leiomyosarcomas. A significant difference was found between spindle cell melanoma and all other examined sarcomatoid neoplasms except angiosarcoma. While diffuse (and often strong) PRAME expression is more frequently observed in spindle cell melanoma than MPNST, sarcomatoid SCC, AFX, PDS, and high-grade leiomyosarcoma, its limited sensitivity and specificity caution against its use as a standalone diagnostic marker. PRAME may complement other epigenetic or lineage-specific markers and should only be used as part of an immunohistochemical panel when evaluating these sarcomatoid neoplasms.

PRAME Expression in Cancer. A Systematic Immunohistochemical Study of >5800 Epithelial and Nonepithelial Tumors

Preferentially expressed antigen in melanoma (PRAME) is considered a useful marker in the differential diagnosis between malignant melanoma and its melanocytic mimics. Recently PRAME expression was documented in nonmelanocytic tumors, but much of the data are based on mRNA studies. This investigation evaluated PRAME expression in the spectrum of normal tissues and >5800 human tumors using immunohistochemistry and EP461 monoclonal antibody. In normal tissues, PRAME was expressed in the testis and proliferative endometrium. In tumors, PRAME was variably expressed in malignancies of different lineages. Among epithelial tumors, >50% of PRAME-positive lesions were found among endometrial carcinomas (82%), uterine serous carcinomas (82%), uterine carcinosarcomas (60%), ovarian clear cell carcinomas (90%), ovarian serous carcinomas (63%), adenoid cystic carcinomas (81%), seminomas (78%), thymic carcinomas (75%), and basal cell carcinomas (62%). In mesenchymal and neuroectodermal malignancies, PRAME was frequently expressed in synovial sarcoma (71%), myxoid liposarcoma (76%), neuroblastoma (61%) and metastatic melanoma (87%). Also, PRAME was consistently expressed in 4 melanomas that lacked all melanoma markers including S100 protein and SOX10 but harbored typical for melanoma BRAF or NRAS driver mutations. However, strong and diffuse PRAME immunoreactivity was seen in many types of nonmelanocytic poorly differentiated carcinomas and sarcomas. Based on this study, PRAME is a relatively unspecific immunohistochemical marker, which limits its use in diagnostic surgical pathology. However, immunohistochemistry is a reliable and unexpensive method useful in detecting PRAME-positive malignancies for potential immunotherapy.

PRAME Immunoexpression in 275 Cutaneous Melanocytic Lesions: A Double Institutional Experience

In recent years, the preferentially expressed antigen in melanoma (PRAME) has also been used in the histopathological diagnosis of melanocytic lesions, in order to understand if it could constitute a valid, inexpensive, and useful resource in dermatopathological fields. We performed a double-center study to evaluate whether the data on the usefulness and possible limitations of PRAME could also be confirmed by our group. From 1 December 2021 to 29 March 2022, we collected 275 cases of melanocytic lesions that were immunostained with PRAME (Ab219650) and rabbit monoclonal antibody (Abcam). To better correlate the PRAME expression with its nature (benign, uncertain potential for malignancy, or malignant), we categorized PRAME tumor cells' percentage positivity and intensity of immunostaining in a cumulative score obtained by adding the quartile of positive tumor cells (0, 1+, 2+, 3+, 4+) to the PRAME expression intensity in tumor cells (0, 1+, 2+, 3+). Of these 275 lesions, 136 were benign, 12 were of uncertain potential for malignancy (MELTUMP or SAMPUS or SPARK nevus), and 127 were malignant. The immunoexpression of PRAME was completely negative in 125/136 benign lesions (91.9%), with only a few positive melanocytes (1+) and intensity 1+ in the remaining 11 cases (8.1%). Of the 127 cases of melanoma (superficial spreading, lentigo maligna, and pagetoid histotypes), PRAME was strongly positive in 104/127 cases (81.8%) with intensity 4+ and 3+. In 17 cases (13.3%; melanoma spindle and nevoid cell histotypes), PRAME was positive in percentage 2+ and with intensity ranging from 2+ to 3+. In 7 cases (5.5%) of desmoplastic melanoma, PRAME was 1+ positive and/or completely negative. Of the 12 cases of lesions with uncertain potential for malignancy, the immunoexpression of PRAME was much more heterogeneous and irregularly distributed throughout the lesion. These data are perfectly in agreement with the current literature, and they demonstrate that the reliability of PRAME is quite high, but its use cannot cause physicians to disregard the morphological information and the execution of other ancillary immunohistochemical stains such as Melan-A, HMB-45, MiTF, and SOX-10.

The Role of Immunotherapy in the Management of Soft Tissue Sarcomas: Current Landscape and Future Outlook

Soft tissue sarcomas (STS) are a subset of sarcoma, a rare group of heterogeneous malignancies of mesenchymal origin. Current standard of care involves surgical resection with systemic chemotherapy used to treat high-risk localized and metastatic disease. Though classically thought to be immunologically quiet tumors, STS interact with the immune system, undergoing immunoediting that alters tumor immunogenicity and the tumor microenvironment. Recent advances with immune checkpoint inhibition have led to clinical trials exploring the efficacy of immunotherapy in treating STS. Results from these trials point to histologic subtype-specific clinical activity of immune checkpoint blockade. In addition, combinatorial strategies adding immune checkpoint inhibition to local or systemic therapies for STS have further increased their efficacy. Targeted immunotherapies using engineered T-cell receptor-based approaches also show increasing promise as treatment options for some patients with STS. Adoptive transfer of autologous T cells targeting NY-ESO-1 and MAGE-A4 have high response rates in sarcomas expressing these antigens, although recurrence is often seen in responding patients. Future work must focus on identifying primary and acquired mechanisms of resistance to these therapies, and extend T-cell receptor discovery to other tumor-associated antigens.

Prognostic attributes of immune signatures in soft tissue sarcomas show differential dependencies on tumor mutational burden

Background

Cellular and intrinsic markers of sarcoma immunogenicity are poorly understood. To gain insight into whether tumor–immune interactions correlate with clinical aggressiveness, the authors examined the prognostic significance of immune gene signatures in combination with tumor mutational burden (TMB) and cancer–testis antigen (CTA) expression.

Methods

RNA sequencing and clinical data of 259 soft tissue sarcomas from The Cancer Genome Atlas project were used to investigate associations between published immune gene signatures and patient overall survival (OS) in the contexts of TMB, as computed from whole‐exome sequencing data, and CTA gene expression. Multivariate Cox proportional hazards regression models and log‐rank tests were used to assess survival associations.

Results

Immune signature scores that reflected in part the intratumoral abundance of cytotoxic T cells showed significant positive associations with OS. However, the prognostic power of the T‐cell signatures was highly dependent on TMB‐high status, consistent with protective effects of tumor‐infiltrating T cells in tumors with elevated antigenicity. In TMB‐low tumors, a signature of infiltrating plasma B cells was significantly and positively associated with OS, independent of T‐cell signature status. Although tumor subtypes based on differential expression patterns of CTA genes showed different survival associations within leiomyosarcoma and myxofibrosarcoma histologies, neither CTA nor histologic subtype interacted with the T‐cell–survival association.

Conclusions

Signatures of T‐cell and plasma B‐cell infiltrates were associated with a survival benefit in soft tissue sarcomas. TMB, but not CTA expression, influenced the prognostic power of T‐cell–associated, but not plasma B‐cell–associated, survival.

Lay summary

Clinical data and RNA analysis of 259 soft tissue sarcomas from The Cancer Genome Atlas project were used to investigate associations between five published gene immune cell expression signatures and survival in the context of tumor mutations.

Activated T cells had a significant positive association with patient survival.

Although high tumor mutation burden was associated with good survival, the prognostic power of T‐cell signatures was highly dependent on tumor mutational status, consistent with protective effects of tumor‐infiltrating T cells in tumors with high levels of antigens.

In low tumor mutation‐bearing tumors, plasma B cells were positively associated with survival.

Signatures of T‐cell and plasma B‐cell infiltrates are associated with survival benefit in soft tissue sarcomas, and tumor mutational burden (TMB), but not cancer–testis antigen expression, is a tumor‐intrinsic determinant of T‐cell–associated survival, but not plasma B‐cell–associated survival. Although high TMB trended toward an association with good survival, the prognostic power of the T‐cell signatures was highly dependent on TMB‐high status, consistent with the protective effects of tumor‐infiltrating T cells in tumors with elevated antigenicity; however, in TMB‐low tumors, a signature of infiltrating plasma B cells was positively associated with overall survival, independent of T‐cell signature status.

Cutaneous Melanomas: A Single Center Experience on the Usage of Immunohistochemistry Applied for the Diagnosis

Cutaneous melanoma (cM) is the deadliest of all primary skin cancers. Its prognosis is strongly influenced by the stage at diagnosis, with early stages having a good prognosis and being potentially treatable with surgery alone; advanced stages display a much worse prognosis, with a high rate of recurrence and metastasis. For this reason, the accurate and early diagnosis of cM is crucial-misdiagnosis may have extremely dangerous consequences for the patient and drastically reduce their chances of survival. Although the histological exam remains the "gold standard" for the diagnosis of cM, a continuously increasing number of immunohistochemical markers that could help in diagnosis, prognostic characterization, and appropriate therapeutical choices are identified every day, with some of them becoming part of routine practice. This review aims to discuss and summarize all the data related to the immunohistochemical analyses that are potentially useful for the diagnosis of cM, thus rendering it easier to appropriately applicate to routine practice. We will discuss these topics, as well as the role of these molecules in the biology of cM and potential impact on diagnosis and treatment, integrating the literature data with the experience of our surgical pathology department.

Comparative Analysis of PRAME Expression in 127 Acral and Nail Melanocytic Lesions

PRAME (PReferentially expressed Antigen in MElanoma), a cancer testis antigen expressed in low levels in gonadal, endometrial, and adrenal gland tissues, has been recently considered a valuable tool in the differential diagnosis between benign and malignant melanocytic lesions. The aim of the current study is to perform PRAME immunostaining on a large series of benign and malignant acral lesions to evaluate the reproducibility of data reported in the literature and to validate PRAME as an affordable tool in the differential diagnosis between benign and malignant acral melanocytic tumors. Immunohistochemical analysis for PRAME was performed in 127 benign and malignant acral and nail melanocytic lesions. To better correlate PRAME expression with the nature (benign vs. malignant) of the lesions, we categorized PRAME tumor cells percentage positivity and intensity in a cumulative score obtained by adding the quartile of positive tumor cells (0, 1+, 2+, 3+, 4+) to PRAME expression intensity in tumor cells (0, 1+, 2+, 3+). Adopting an arbitrary PRAME expression score of < 5 versus ≥5 resulted in a correct identification of 82.5% of benign and 87.1% of malignant lesions. PRAME immunohistochemistry demonstrated good sensitivity and specificity in the diagnosis of acral melanocytic lesions, however, in line with the previous literature, we identified a subset of challenging cases such as acral Spitz nevi, in situ melanomas, and small, thin, invasive melanomas in which PRAME did not correlate with morphologic features. This suggests that PRAME can be a valid tool to be incorporated in a diagnostic clinicopathologic algorithm, subject to morphologic characteristics.

JW. Multivariant Transcriptome Analysis Identifies Modules and Hub Genes Associated with Poor Outcomes in Newly Diagnosed Multiple Myeloma Patients

The molecular mechanisms underlying chemoresistance in some newly diagnosed multiple myeloma (MM) patients receiving standard therapies (lenalidomide, bortezomib, and dexamethasone) are poorly understood. Identifying clinically relevant gene networks associated with death due to MM may uncover novel mechanisms, drug targets, and prognostic biomarkers to improve the treatment of the disease. This study used data from the MMRF CoMMpass RNA-seq dataset (N = 270) for weighted gene co-expression network analysis (WGCNA), which identified 21 modules of co-expressed genes. Genes differentially expressed in patients with poor outcomes were assessed using two independent sample t-tests (dead and alive MM patients). The clinical performance of biomarker candidates was evaluated using overall survival via a log-rank Kaplan-Meier and ROC test. Four distinct modules (M10, M13, M15, and M20) were significantly correlated with MM vital status and differentially expressed between the dead (poor outcomes) and the alive MM patients within two years. The biological functions of modules positively correlated with death (M10, M13, and M20) were G-protein coupled receptor protein, cell-cell adhesion, cell cycle regulation genes, and cellular membrane fusion genes. In contrast, a negatively correlated module to MM mortality (M15) was the regulation of B-cell activation and lymphocyte differentiation. MM biomarkers CTAG2, MAGEA6, CCND2, NEK2, and E2F2 were co-expressed in positively correlated modules to MM vital status, which was associated with MM's lower overall survival.

Adult Soft-Tissue Sarcomas of the Extremities

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Soft-tissue sarcomas (STS) in adults comprise a heterogeneous group of tumors of mesenchymal origin that share similar biological patterns of local tumor growth and metastatic dissemination.

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The judicious use of imaging studies, biopsy techniques, and pathological evaluations is essential for accurate diagnosis and for planning treatment strategy.

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Wide local resection and radiation therapy form the cornerstone of management of high-grade STS. The role of adjuvant radiation therapy is questionable in the management of small (≤5 cm) superficial lesions that can be resected with negative margins. Chemotherapy given to patients who have nonmetastatic, high-grade STS results in varying benefit in terms of local tumor control and overall survival.

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Coordinated care by a multidisciplinary team of trained surgeons, medical oncologists, radiologists, radiation oncologists, and pathologists has been documented to improve local tumor control and the overall survival of patients with STS.

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Although considerable progress in tumor diagnostics and targeted therapies has been made over the past 2 decades, recommendations and controversies relating to tumor imaging and margins of resection have not changed.

Differential gene expression and network analysis in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignancy with a poor prognosis, whose biomarkers have not been studied in great detail. We have collected genomic data of HNSCC patients from The Cancer Genome Atlas (TCGA) and analyzed them to get deeper insights into the gene expression pattern. Initially, 793 differentially expressed genes (DEGs) were categorized, and their enrichment analysis was performed. Later, a protein-protein interaction network for the DEGs was constructed using the STRING plugin in Cytoscape to study their interactions. A set of 10 hub genes was selected based on Maximal Clique Centrality score, and later their survival analysis was studied. The elucidated set of 10 genes, i.e., PRAME, MAGEC2, MAGEA12, LHX1, MAGEA3, CSAG1, MAGEA6, LCE6A, LCE2D, LCE2C, referred to as potential candidates to be explored as HNSCC biomarkers. The Kaplan-Meier overall survival of the selected genes suggested that the alterations in the candidate genes were linked to the decreased survival of the HNSCC patients. Altogether, the results of this study signify that the genomic alterations and differential expression of the selected genes can be explored in therapeutic interpolations of HNSCC, exploiting early diagnosis and target-propelled therapy.

PRAME Expression in Challenging Dermal Melanocytic Neoplasms and Soft Tissue Tumors With Melanocytic Differentiation

ABSTRACT

Preferentially expressed antigen in melanoma (PRAME) is an immunohistochemical biomarker that is diffusely expressed in most cutaneous melanomas and is negative in most benign nevi. Histologically challenging dermal melanocytic neoplasms, such as cellular blue nevi (CBN) and deep penetrating nevi (DPN), and soft tissue tumors with melanocytic differentiation, such as clear cell sarcoma and perivascular epithelioid cell tumor, may resemble primary or metastatic melanoma. PRAME immunohistochemistry (IHC) was applied to archived formalin-fixed, paraffin-embedded specimens of various dermal melanocytic neoplasms and soft tissue neoplasms with melanocytic differentiation. Staining was graded based on the percentage of melanocytes labeled (0-4+ as previously reported). The gold standard was final pathologic diagnosis using histologic, immunophenotypic, and in some cases molecular findings. Fifty-four cases were evaluated. 62.5% (5/8) of blue nevus-like melanomas and 50% (1/2) of DPN-like melanomas were PRAME positive (4+). Of the other tumors, 100% (20/20) of CBN (including 1 atypical CBN with borderline features); 100% (12/12) of DPN, combined DPN, or borderline DPN; 88.9% (8/9) of perivascular epithelioid cell tumors; and 100% (3/3) of clear cell sarcoma were PRAME negative (0-2+). Within the borderline categories specifically, all 8 tumors (1 borderline CBN and 7 borderline DPN) showed low (0-2+) PRAME expression. Overall, the sensitivity for melanoma in this context was 60%, with a specificity of 97.7%. Although our sample size is limited, the results suggest that IHC staining for PRAME may be useful in supporting a diagnosis of melanoma in the setting of challenging dermal melanocytic neoplasms and other epithelioid neoplasms with melanocytic differentiation. However, PRAME IHC lacks sensitivity in this context.

Expression of CTAG1B clone EPR13780 versus DDIT3 gene rearrangement distinguishes myxoid liposarcoma from its mimics with detection of novel DDIT3 gene copy number variations

Myxoid liposarcoma (MLPS) has different patterns that are often difficult to distinguish from other soft tissue lesions. MLPS is characterized by a reciprocal translocation involving the DNA Damage Inducible Transcript 3 gene (DDIT3) that can be detected using fluorescent in situ hybridization (FISH). Recently, the marker for cancer testis antigen 1b (CTAG1B) was found to be expressed in MLPS. The aim of the present study was to assess the potential use immunohistochemistry (IHC) for CTAG1B expression and DDIT3 rearrangement to diagnose MLPS and distinguish it from similar lesions. Out of 29 cases including MLPS and its mimics, CTAG1B was expressed in 92.86% of cases of MLPS and 20% of its mimics. DDIT3 rearrangement was 100% sensitive and 92.86% specific in distinguishing MLPS from its mimics. The DDIT3 rearrangement was found to be more sensitive but less specific than cytoplasmic expression of CTAG1B marker. DDIT3 polysomy and amplification were detected in some cases. Therefore, both CTAG1B expression and FISH for DDIT3 gene can be used to distinguish MLPS from similar tumors. The use of both immunohistochemistry for CTAG1B in addition to DDIT3 gene rearrangement detection by FISH was more specific than using either of them alone. However, the DDIT3 gene rearrangement alone was the most sensitive test for distinguishing MLPS from its mimics.

PRAME expression in cellular neurothekeoma: A study of 11 cases

BACKGROUND

Preferentially expressed antigen in melanoma (PRAME) has been widely investigated in the skin, mainly in melanocytic tumors, and constitutes an aid in differentiating benign from malignant lesions. Very few studies have been performed on non-melanocytic tumors.

MATERIALS

We investigated the immunohistochemical expression of PRAME on a series of 11 neurothekeomas (NTKs), together with 3 cases of nerve sheath myxoma (NSM) and 1 case of plexiform fibrohistiocytic tumor (PFT), in order to evaluate the presence and usefulness of this marker in their differential diagnosis.

RESULTS

PRAME was variably expressed in all cases of NTK, with moderate intensity in three cases and faint in the remaining cases; on the contrary, cases of NSM and PFT were negative.

CONCLUSIONS

This study expands the entities of cutaneous non-melanocytic tumors expressing PRAME, and confirms that this marker is not restricted to malignant tumors. Expression of PRAME in NTK does not seem to be related to distinctive histopathologic features.

The Challenge of Melanocytic Lesions in Pediatric Patients: Clinical-Pathological Findings and the Diagnostic Value of PRAME

Pediatric melanoma is a rare disease especially in children aged younger than 10 years old. Recent estimates report a rise of disease incidence in both adults and children. Diagnostic work-up is challenging in pediatric melanoma, as it displays a wide range of clinical presentations. Immunohistochemical biomarkers have been reported as predictors of malignancy in melanoma, however data specific to pediatric melanoma are poor. Our study aims to contribute to provide evidence of pediatric melanoma clinical features and differential diagnosis in this patient population. We describe our experience with a retrospective case series of pigmented skin lesions including malignant melanoma, atypical spitzoid tumor, and benign nevi in children and adolescents aged less than 16 years. We described the clinical and demographic characteristics of the cohort and evaluated the immunohistochemical expression of the PReferentially expressed Antigen in MElanoma (PRAME) for differential diagnosis of melanoma in children. The series displayed a similar distribution of melanoma between males and females, and the most common site of melanoma onset were the upper and lower limbs. In our cohort, PRAME was negative in most cases. Focal and slight positivity (from 1 to 5% of the neoplastic cells) was observed in four cases (two Spitz nevi and two atypical Spitz tumors). A moderate positivity in 25% of the neoplastic cells was observed in one case of atypical Spitz tumor. Immunohistochemical expression of PRAME might be useful in the differential diagnosis of malignant melanoma.

PRAME immunohistochemistry as an adjunct for diagnosis and histological margin assessment in lentigo maligna

AIMS

Lentigo maligna (LM), the most common type of melanoma in situ, is a diagnostically challenging lesion for pathologists due to abundant background melanocytic hyperplasia in sun-damaged skin. Currently, no laboratory methods reliably distinguish benign from malignant melanocytes. However, preferentially expressed antigen in melanoma (PRAME) has shown promise in this regard, and could potentially be applied to diagnosis and margin assessment in difficult cases of LM.

METHODS AND RESULTS

Ninety-six cases with a diagnosis of LM (n = 77) or no residual LM (n = 19) following initial biopsy were identified and stained with an antibody directed towards PRAME. Immunohistochemistry (IHC) was scored as positive or negative, and measurement of histological margins by PRAME was performed and compared to the measurement of histological margins using conventional methods [haematoxylin and eosin (H&E) and/or sex-determining region Y-box 10 (SOX10) and/or Melan-A]. Of cases with LM, 93.5% (72 of 77) were PRAME+ and 94.7% (18 of 19) of cases with no residual LM were PRAME- . Of the 35 cases with no margin involvement by PRAME or conventional assessment, 14 cases (40.0%) had no difference in measurement, 17 (48.6%) had a difference of 1 mm or less and four (11.4%) differed by between 1 and 3.5 mm. There was a high correlation between margin assessment methods (r = 0.97, P < 0.0001).

CONCLUSIONS

PRAME IHC is a sensitive (93.5%) and specific (94.7%) method for diagnosing LM on biopsy and excision, and measurement of histological margins by PRAME shows a high correlation with conventional methods for margin assessment. Furthermore, the nuclear expression of PRAME makes it a good target for use in dual-colour IHC stains.

PRAME Immunohistochemistry as an Ancillary Test for the Assessment of Melanocytic Lesions

PRAME (PReferentially expressed Antigen in MElanoma) is a melanoma-associated antigen expressed in cutaneous and ocular melanomas and some other malignant neoplasms, while its expression in normal tissue and benign tumors is limited. Detection of PRAME protein expression by immunohistochemistry in a cohort of 400 melanocytic tumors showed diffuse nuclear immunoreactivity for PRAME in most metastatic and primary melanomas. In contrast, most nevi were negative for PRAME or showed nondiffuse immunoreactivity. The difference in the extent of immunoreactivity for PRAME in unambiguous melanocytic tumors prompted the study of PRAME as an ancillary tool for evaluating melanocytic lesions in more challenging scenarios.

Is immunotherapy in the future of therapeutic management of sarcomas?

Sarcomas are rare, ubiquitous and heterogeneous tumors usually treated with surgery, chemotherapy, target therapy, and radiotherapy. However, 25-50% of patients experience local relapses and/or distant metastases after chemotherapy with an overall survival about 12-18 months. Recently, immuno-therapy has revolutionized the cancer treatments with initial indications for non-small cell lung cancer (NSCLC) and melanoma (immune-checkpoint inhibitors).Here, we provide a narrative review on the topic as well as a critical description of the currently available trials on immunotherapy treatments in patients with sarcoma. Given the promising results obtained with anti-PD-1 monoclonal antibodies (pembrolizumab and nivolumab) and CAR-T cells, we strongly believe that these new immunotherapeutic approaches, along with an innovative characterization of tumor genetics, will provide an exciting opportunity to ameliorate the therapeutic management of sarcomas.

Analysis of LAGEs Family Gene Signature and Prognostic Relevance in Breast Cancer

Breast cancer (BRCA) is one of the most complex diseases and involves several biological processes. Members of the L-antigen (LAGE) family participate in the development of various cancers, but their expressions and prognostic values in breast cancer remain to be clarified. High-throughput methods for exploring disease progression mechanisms might play a pivotal role in the improvement of novel therapeutics. Therefore, gene expression profiles and clinical data of LAGE family members were acquired from the cBioportal database, followed by verification using the Oncomine and The Cancer Genome Atlas (TCGA) databases. In addition, the Kaplan-Meier method was applied to explore correlations between expressions of LAGE family members and prognoses of breast cancer patients. MetaCore, GlueGo, and GluePedia were used to comprehensively study the transcript expression signatures of LAGEs and their co-expressed genes together with LAGE-related signal transduction pathways in BRCA. The result indicated that higher LAGE3 messenger (m)RNA expressions were observed in BRCA tissues than in normal tissues, and they were also associated with the stage of BRCA patients. Kaplan-Meier plots showed that overexpression of LAGE1, LAGE2A, LAGE2B, and LAGE3 were highly correlated to poor survival in most types of breast cancer. Significant associations of LAGE family genes were correlated with the cell cycle, focal adhesion, and extracellular matrix (ECM) receptor interactions as indicated by functional enrichment analyses. Collectively, LAGE family members' gene expression levels were related to adverse clinicopathological factors and prognoses of BRCA patients; therefore, LAGEs have the potential to serve as prognosticators of BRCA patients.

Cancer Testis Antigens and Immunotherapy: Expression of PRAME Is Associated with Prognosis in Soft Tissue Sarcoma

(1) Background: PRAME, NY-ESO-1, and SSX2 are cancer testis antigens (CTAs), which are expressed in testicular germ cells with re-expression in numerous cancer types. Their ability to elicit humoral and cellular immune responses have rendered them promising targets for cancer immunotherapy, but they have never been studied in a large and well-characterised cohort of soft tissue sarcomas (STS). (2) Methods: On a protein level, we examined PRAME, NY-ESO-1, and SSX2 expression in tumour tissues of 249 high-risk STS using immunohistochemistry. We correlated expression levels with clinicopathological parameters including tumour-infiltrating lymphocyte (TIL) counts, grading, and long-term survival. (3) Results: Expression of PRAME, NY-ESO-1, and SSX2 was observed in 25 (10%), 19 (8%), and 11 (4%) of 249 specimens with distinct patterns for histo-subtypes. Expression of PRAME was associated with shorter patient survival (p = 0.005) and higher grade (G2 vs. G3, p = 0.001), while NY-ESO-1 expression was correlated with more favourable survival (p = 0.037) and lower grade (G2 vs. G3, p = 0.029). Both PRAME and NY-ESO-1 expression were more frequent in STS with low TIL counts. In multivariate analysis, high PRAME and low SSX2 expression levels as well as metastatic disease and non-radical resections were independent predictors of shorter overall survival. (4) Conclusions: CTAs PRAME, NY-ESO-1, and SSX2 show distinct expression patterns in different STS subtypes. These results demonstrate their prognostic relevance and may guide future immunotherapeutic approaches in STS.

PRAME expression in melanocytic proliferations with intermediate histopathologic or spitzoid features

BACKGROUND

PRAME (PReferentially expressed Antigen in MElanoma) has shown utility in distinguishing melanoma from benign melanocytic lesions, but knowledge of its expression pattern in intermediate melanocytic and spitzoid proliferations is limited.

METHODS

Immunohistochemical expression of PRAME was examined in 112 melanocytic proliferations with intermediate histopathologic or spitzoid features.

RESULTS

Any intensity of nuclear PRAME staining in at least 60% of lesional melanocytes was determined as the best threshold for diffuse staining in this cohort. Nearly all non-spitzoid melanomas (23/24; 95.8%) demonstrated diffuse PRAME expression. PRAME was completely negative in 95.6% (43/45) of mitotically-active nevi, traumatized nevi, nevi with persistent/recurrent features, and dysplastic nevi. Most Spitz nevi (15/20) and atypical Spitz tumors (10/13) entirely lacked PRAME expression. One Spitz nevus, one atypical Spitz tumor, and one spitzoid melanoma (1/2) demonstrated diffuse PRAME expression.

CONCLUSIONS

Although diffuse PRAME expression is generally limited to malignant melanoma, benign Spitz nevi and atypical Spitz tumors can infrequently express diffuse PRAME. PRAME immunohistochemistry can be useful in the evaluation of atypical melanocytic proliferations with intermediate histopathologic features but should be interpreted with caution in the setting of spitzoid neoplasms.

Comparison of Immunohistochemistry for PRAME With Cytogenetic Test Results in the Evaluation of Challenging Melanocytic Tumors

PRAME (PReferentially expressed Antigen in MElanoma) is a melanoma-associated antigen. Although diffuse immunoreactivity for PRAME is found in most primary cutaneous melanomas, melanocytic nevi express PRAME usually only in a subpopulation of tumor cells or not at all. Hence, testing for PRAME expression has the potential to provide useful information for the assessment for diagnostically ambiguous melanocytic neoplasms. Many of the latter tumors are currently studied by cytogenetic methods for ancillary evidence in support of or against a diagnosis of melanoma. In this study we analyzed 110 diagnostically problematic melanocytic tumors comparing results for PRAME immunohistochemistry (IHC) with those from fluorescence in situ hybridization and/or single nucleotide polymorphism-array, and each with the final diagnostic interpretation. In 90% of cases there was concordance between PRAME IHC and cytogenetic tests results, and in 92.7% concordance between PRAME IHC and the final diagnosis. The high concordance between PRAME IHC and cytogenetic test results as well as the final diagnosis supports the use of PRAME IHC as an ancillary test in the evaluation of ambiguous primary cutaneous melanocytic neoplasms, especially given its practical advantage of lower cost and faster turnaround over cytogenetic or gene expression studies. However, our results indicate that PRAME IHC and cytogenetic tests for melanocytic tumors are not entirely interchangeable and on occasion each type of test may yield false-negative or false-positive results.

The role of the cancer testis antigen PRAME in tumorigenesis and immunotherapy in human cancer

Preferentially expressed antigen in melanoma (PRAME), which belongs to the cancer/testis antigen (CTA) gene family, plays a pivotal role in multiple cellular processes and immunotherapy response in human cancers. PRAME is highly expressed in different types of cancers and is involved in cell proliferation, apoptosis, differentiation and metastasis as well as the outcomes of patients with cancer. In this review article, we discuss the potential roles and physiological functions of PRAME in various types of cancers. Moreover, this review highlights immunotherapeutic strategies that target PRAME in human malignancies. Therefore, the modulation of PRAME might be useful for the treatment of patients with cancer.

Cancer/testis antigens expression during cultivation of melanoma and soft tissue sarcoma cells

BACKGROUND

Autologous dendritic cells (DC) loaded with tumor-associated antigens (TAAs) are a promising approach for anticancer immunotherapy. Polyantigen lysates appear to be an excellent source of TAAs for loading onto the patient's dendritic cells. Cancer/testis antigens (CTA) are expressed by a wide range of tumors, but are minimally expressed on normal tissues, and could serve as a universal target for immunotherapy. However, CTA expression levels can vary significantly in patients with the same tumor type. We proposed that patients who do not respond to DC-based therapy may have distinct features of the CTA expression profile on tumor cells.

PATIENTS AND METHODS

We compared the gene expression of the principal families CTA in 22 melanoma and 27 soft tissue and bone sarcomas cell lines (STBS), received from patients and used for DC vaccine preparation.

RESULTS

The majority (47 of 49, 95.9%) cell lines showed CTA gene activity. The incidence of gene expression of GAGE, NYESO1, MAGEA1, PRAME's was significantly different (adj. p < 0.05) between melanoma and sarcoma cell lines. The expression of the SCP1 gene was detected neither in melanoma cells nor in the STBS cells. Clustering by the gene expression profile revealed four different expression patterns. We found three main patterns types: hyperexpression of multiple CTA, hyperexpression of one CTA with almost no expression of others, and no expression of CTA. All clusters types exist in melanoma and sarcoma cell lines. We observed dependence of killing efficacy from the PRAME (rho = 0.940, adj. p < 0.01) expression during real-time monitoring with the xCELLigence system of the interaction between melanoma or sarcoma cells with the T-lymphocytes activated by the lysate of selected allogenous melanoma cell lines with high expression of CTA.

CONCLUSION

Our results demonstrate that one can use lysates from allogeneic melanoma cell lines as a source of CTA for DC load during the production of anticancer vaccines for the STBS treatment. Patterns of CTA expression should be evaluated as biomarkers of response in prospective clinical trials.

Cancer testis antigens in sarcoma: Expression, function and immunotherapeutic application

Sarcomas are a group of heterogeneous malignancies of mesenchymal origin. Patient outcomes remain especially grim for those with recurrent or metastatic disease, and current therapeutic strategies have not significantly improved outcomes over the past few decades. This has led to a number of studies assessing novel therapies. Cancer testis antigens (CTAs) are tumor-associated antigens with physiologic expression in the testis and various malignancies, including sarcomas. Genes encoding CTAs include MAGE, NY-ESO-1, PRAME, TRAG-3/CSAGE, and SSX. The importance and function of CTAs in tumorigenesis have gained recognition in recent years. They are also proving as robust diagnostic and prognostic biomarkers. Therapeutically, antigens derived from CTAs are highly recognizable by T lymphocytes and therefore capable of generating a potent antitumor immune response. CTAs are, therefore, promising targets for novel immunotherapies. Here we review the emerging works on expression, function, and immunotherapeutic application of CTAs in sarcoma therapy.

PRAME Expression in Melanocytic Tumors

PRAME (PReferentially expressed Antigen in MElanoma) is a melanoma-associated antigen that was isolated by autologous T cells in a melanoma patient. While frequent PRAME mRNA expression is well documented in cutaneous and ocular melanomas, little is known about PRAME protein expression in melanocytic tumors. In this study we examined the immunohistochemical expression of PRAME in 400 melanocytic tumors, including 155 primary and 100 metastatic melanomas, and 145 melanocytic nevi. Diffuse nuclear immunoreactivity for PRAME was found in 87% of metastatic and 83.2% of primary melanomas. Among melanoma subtypes, PRAME was diffusely expressed in 94.4% of acral melanomas, 92.5% of superficial spreading melanomas, 90% of nodular melanomas, 88.6% of lentigo maligna melanomas, and 35% of desmoplastic melanomas. When in situ and nondesmoplastic invasive melanoma components were present, PRAME expression was seen in both. Of the 140 cutaneous melanocytic nevi, 86.4% were completely negative for PRAME. Immunoreactivity for PRAME was seen, albeit usually only in a minor subpopulation of lesional melanocytes, in 13.6% of cutaneous nevi, including dysplastic nevi, common acquired nevi, traumatized/recurrent nevi, and Spitz nevi. Rare isolated junctional melanocytes with immunoreactivity for PRAME were also seen in solar lentigines and benign nonlesional skin. Our results suggest that immunohistochemical analysis for PRAME expression may be useful for diagnostic purposes to support a suspected diagnosis of melanoma. It may also be valuable for margin assessment of a known PRAME-positive melanoma, but its expression in nevi, solar lentigines, and benign nonlesional skin can represent a pitfall and merits further investigations to better assess the potential clinical utility of this marker.

Molecular updates in adipocytic neoplasms✰

Adipocytic neoplasms include a diversity of both benign tumors (lipomas) and malignancies (liposarcomas), and each tumor type is characterized by its own unique molecular alterations driving tumorigenesis. Work over the past 30 years has established the diagnostic utility of several of these characteristic molecular alterations (e.g. MDM2 amplification in well- and dedifferentiated liposarcoma, FUS/EWSR1-DDIT3 gene fusions in myxoid liposarcoma, RB1 loss in spindle cell/pleomorphic lipoma). More recent studies have focused on additional molecular alterations which may have therapeutic or prognostic impact. This review will summarize several of the important molecular findings in adipocytic tumors that have been described over the past 10 years.

Antitumor effect of recombinant Mycobacterium smegmatis expressing MAGEA3 and SSX2 fusion proteins

Mycobacterium smegmatis (M. smegmatis), which is a nonpathogenic and fast-growing mycobacterium, is a potential vaccine vector capable of expressing heterologous antigens. Spontaneous humoral and cellular immune responses have been demonstrated against cancer/testis antigens (CTA), including melanoma-associated antigen A (MAGEA) and SSX. In the present study, recombinant plasmids expressing MAGEA3 and SSX2 were constructed. The recombinant plasmids were transferred into M. smegmatis to generate the novel antitumor DNA vaccine. As MAGEA3 and SSX2 were in different ligation sequences, the two DNA vaccines were recombinant M. smegmatis MAGEA3-SSX2 (rM.S-MS) and recombinant M. smegmatis SSX2-MAGEA3 (rM.S-SM), respectively. The expression levels of Fusion proteins were assessed by western blotting. BALB/c mice were immunized with rM.S and western blot analysis was used to determine whether antibodies against MAGEA3 or SSX2 were produced in immunized mice. EC9706 cells were inoculated into BALB/c nude mice and the mice were maintained until an obvious visible tumor appeared on the back. Subsequently, the blood from the rM.S immunized BALB/c mice was injected into the BALB/c nude mice via the tail vein. In order to evaluate the antitumor effect of the vaccines, tumor volume and weight were measured 5 to 21 days after injection. Mice were euthanized on day 21 of tumor growth, and the tumor was dissected and weighed. The two fusion proteins were expressed in the rM.S and the specific fusion protein antibodies were expressed in the blood of immunized BALB/c mice. The tumor volumes and weight in the recombinant M. smegmatis MAGEA3 (rM.S-M) and recombinant M. smegmatis SSX2 (rM.S-S) groups were significantly reduced compared with the control group. Furthermore, the decrease in tumor volumes and weight in the rM.S-MS and rM.S-SM groups was more severe than in the rM.S-M or rM.S-S groups. There was no significant difference in the antitumor effect of the rM.S-MS and rM.S-SM groups. The present findings suggest that this rM.S may be a potential candidate therapeutic vaccine for the treatment of cancer.

Cancer-testis antigens are predominantly expressed in uterine leiomyosarcoma compared with non-uterine leiomyosarcoma

Leiomyosarcomas account for ~24% of all adult sarcomas, and develop predominantly either in the uterus [uterine leiomyosarcoma (ULMS)] or in deep soft tissue or the retroperitoneum [non-uterine leiomyosarcoma (NULMS)]. Leiomyosarcomas are relatively chemoresistant tumors, and the prognosis of patients with leiomyosarcomas is poor. Cancer-testis (CT) antigens are considered promising immunotherapeutic targets because of their restricted expression in normal tissue, except in the testis. Little is known about the expression of CT antigens in leiomyosarcomas. In the present study, the protein expression of the CT antigens MAGE family member A (MAGEA)1, MAGEA3, MAGEA4, G antigen 7 (GAGE7) and cancer/testis antigen 1 (NY-ESO-1) in ULMS and NULMS were investigated using immunohistochemistry (IHC), and their expression profiles compared. In ULMS and NULMS, positive expression was observed in 11/32 (31%) and 1/31 (3%; MAGEA1), 15/32 (47%) and 5/31 (16%; MAGEA3), 11/32 (34%) and 3/31 (10%; MAGEA4), 23/32 (72%) and 11/31 (35%; GAGE7) and 3/32 (9%) and 0/31 (0%; NY-ESO-1), respectively. The ULMSs demonstrated significantly higher positive expression of MAGEA1 (P=0.0034), MAGEA3 (P=0.0141), MAGEA4 (P=0.0319) and GAGE7 (P=0.0054) compared with the NULMSs. The ULMSs also had significantly higher IHC scores for MAGEA1 (P=0.0023), MAGEA3 (P=0.0474), MAGEA4 (P=0.011), GAGE7 (P=0.0319) and NY-ESO-1 (P=0.0437). The results of the present study support the potential utility of MAGEA1, MAGEA3, MAGEA4 and GAGE7 in ULMS and GAGE7 in NULMS as immunotherapeutic targets.

Immunotherapy for Soft Tissue Sarcoma: Tomorrow Is Only a Day Away

Despite the advances taking place for patients with many types of cancer, to date there has been little success in meeting the great need for novel treatments of advanced soft tissue sarcoma with effective immunologic therapies. Here, we review recent clinical and preclinical data that indicate immune responses against sarcomas occur spontaneously and can also be successfully provoked. Efforts to manipulate the sarcoma immune microenvironment have the potential to eradicate disease and may also sensitize tumors to other tumor-targeted immunotherapeutic approaches. Other approaches, including vaccines and genetic engineering of T cells, offer a promising opportunity to actively direct cytotoxic lymphocytes toward antigen-bearing sarcomas. Drawing parallels with recent advances made in other cancer types, we identify ways in which sarcomas can be included in the ongoing immunotherapy revolution.

Immunotherapeutic approaches to sarcoma

OPINION STATEMENT

Current therapies in advanced sarcomas are primarily based on cytotoxic chemotherapy and have modest efficacy coupled with significant toxicity. Little progress has been made in the field since imatinib was approved for the treatment of gastrointestinal stromal tumor (GIST) in 2002 despite the recent FDA approval of the multi-tyrosine kinase inhibitor pazopanib. Novel therapies are clearly needed. Immunotherapy utilizing checkpoint inhibitors has yielded significant clinical benefit in multiple solid tumors manifesting as durable responses in melanoma, kidney, lung, and bladder cancers, as well as hematologic malignancies. Given the success in several "non-immunogenic" tumors and recent preclinical data, there is sufficient evidence to support the use of immunotherapy in sarcoma. Cytokine-based therapies have shown no benefit in the advanced setting. Two large randomized trials of muramyl tripeptide or of interferon maintenance in resected osteosarcoma patients did not provide unequivocal statistically significant benefit. More promising results have been reported in small studies evaluating vaccines and adoptive T cell therapy in specific subtypes of sarcoma such as synovial sarcoma, which widely expresses the immunogenic cancer testis antigen NY-ESO-1. Emerging approaches with chimeric antigen receptor (CAR)-engineered T cells are hypothesis-generating and thought-provoking. However, the unprecedented clinical activity and excellent safety profile of checkpoint inhibitors targeting programmed death-1 receptor and its ligand (PD-1/PD-L1) have galvanized the field and generated much enthusiasm to harness the power of immunotherapy in pursuit of cures in patients with advanced sarcomas. An ongoing phase II study (SARC028) will hopefully usher an era of investigation of this exciting approach in sarcoma. However, it is unlikely that one agent will carry a universal cure and future approaches need to focus on patient selection as well as on identifying the optimal combination of checkpoint inhibitors with targeted therapy, chemotherapy, or radiation therapy.