p53 immunohistochemical analysis of fusion-positive uterine sarcomas

P53 Gene as a Promising Biomarker and Potential Target for the Early Diagnosis of Reproductive Cancers

One of the crucial aspects of cancer research is diagnosis with specificity and accuracy. Early cancer detection mostly helps make appropriate decisions regarding treatment and metastasis. The well-studied transcription factor tumor suppressor protein p53 is essential for maintaining genetic integrity. p53 is a key tumor suppressor that recognizes the carcinogenic biological pathways and eradicates them by apoptosis. A wide range of carcinomas, especially gynecological such as ovarian, cervical, and endometrial cancers, frequently undergo TP53 gene mutations. This study evaluates the potential of the p53 gene as a biological marker for the diagnosis of reproductive system neoplasms. Immunohistochemistry of p53 is rapid, easy to accomplish, cost-effective, and preferred by pathologists as a surrogate for the analysis of TP53 mutation. Thus, this review lays a groundwork for future efforts to develop techniques using p53 for the early diagnosis of cancer.

The "Other" Uterine Mesenchymal Neoplasms: Recent Developments and Emerging Entities

Uterine mesenchymal neoplasms are a challenging group of tumors that often show overlapping morphologic features and immunohistochemical profiles. The increasing use of molecular testing in these tumors has enabled a better appreciation of their pathobiology, resulting in a wave of emerging neoplasms and improved characterization of ones previously considered exceptionally rare. Identification of specific molecular alterations has permitted targeted therapy options in tumors that were typically unresponsive to conventional therapies, as well as recognition that a subset can have a hereditary basis. This review will discuss the more "common" of the uncommon uterine mesenchymal neoplasms, including inflammatory myofibroblastic tumor, perivascular epithelioid cell tumor, uterine tumor resembling ovarian sex cord tumor, and embryonal rhabdomyosarcoma. This will be followed by an overview of emerging entities, including NTRK-rearranged uterine sarcoma, SMARCA4-deficient uterine sarcoma, KAT6B/A::KANSL1 fusion uterine sarcoma, and MEIS1::NCOA2/1 fusion sarcoma.

An Unusual Endometrial Stromal Neoplasm With JAZF1-BCORL1 Rearrangement

Endometrial stromal tumors represent the second most common category of uterine mesenchymal tumors. Several different histologic variants and underlying genetic alterations have been recognized, one such being a group associated with BCORL1 rearrangements. They are usually high-grade endometrial stromal sarcomas, often associated with prominent myxoid background and aggressive behavior. Here, we report an unusual endometrial stromal neoplasm with JAZF1-BCORL1 rearrangement and briefly review the literature. The neoplasm formed a well-circumscribed uterine mass in a 50-yr-old woman and had an unusual morphologic appearance that did not warrant a high-grade categorization. It was characterized by a predominant population of epithelioid cells with clear to focally eosinophilic cytoplasm growing in interanastomosing cords and trabeculae set in a hyalinized stroma as well as nested and fascicular growths imparting focal resemblance to a uterine tumor resembling ovarian sex-cord tumor, PEComa, and a smooth muscle neoplasm. A minor storiform growth of spindle cells reminiscent of the fibroblastic variant of low-grade endometrial stromal sarcoma was also noted but conventional areas of low-grade endometrial stromal neoplasm were not identified. This case expands the spectrum of morphologic features seen in endometrial stromal tumors, especially when associated with a BCORL1 fusion and highlights the utility of immunohistochemical and molecular techniques in the diagnosis of these tumors, not all of which are high grade.

p53 as Exemplar Next-Generation Immunohistochemical Marker: A Molecularly Informed, Pattern-Based Approach, Methodological Considerations, and Pan-Cancer Diagnostic Applications

This review is based on a webinar I presented for the International Society for Immunohistochemistry and Molecular Morphology (ISIMM) in February 2022. It is intended that all ISIMM webinars will ultimately be published in AIMM as review articles. This work is also dedicated to Clive Taylor, who has deeply impacted my career. It presents a molecularly informed, pattern-based approach to p53 immunohistochemistry interpretation, methodological considerations (ie, antibody selection, optimization, validation, controls, and external quality assessment), and pan-cancer diagnostic applications, including those drawn from gastrointestinal, genitourinary, gynecological, neuroendocrine, hematologic, and neuropathology. It intends to prove the thesis statement that p53 is an exemplar next-generation immunohistochemical marker "born" ahead of its time.

An Unusual Benign Uterine Stromal Spindle Cell Tumor Harboring JAZF1::BCORL1

Uterine mesenchymal lesions demonstrate various underlying genomic alterations involving MED12 , JAZF1 , YWHAE , BCOR , and ALK genes, among others. Recent publications describe a subset of high-grade endometrial stromal sarcoma lesions harboring BCORL1 gene aberrations including JAZF1::BCORL1 . Herein, we present an unusual benign endomyometrial spindle cell lesion that defies classificatory efforts by demonstrating mixed histomorphologic and immunohistochemical features of endometrial stromal nodule, leiomyoma, and uterine inflammatory myofibroblastic tumor while harboring a JAZF1::BCORL1 . The lesion was found in a 43-yr-old woman with pelvic pain and heavy menses as a 5.5 cm well-circumscribed ulcerated mass fungating from the cervical os. Microscopic examination revealed a polypoid, well-circumscribed, moderately cellular endomyometrial tumor composed by bland spindle cells haphazardly disposed within a slightly edematous stroma enriched by a delicate network of thin-walled vessels that were occasionally encircled by the tumor cells. Unequivocal evidence of tongue-like growth pattern into the myometrium, tumor-type necrosis or increased mitotic activity was not identified after sampling the entire lesion. The lesion showed patchy immunoreactivity for both smooth muscle actin-alpha and desmin while negative for CD10, HMB45, ALK (D5F3), and BCOR. An Archer FusionPlex panel assay demonstrated a fusion involving both exons 4 from the JAZF1 and BCORL1 genes. The JAZF1::BCORL1 has not, to the best of our knowledge, been previously reported in a benign/low-grade mesenchymal uterine lesion.

Molecular-Based Immunohistochemical Algorithm for Uterine Leiomyosarcoma Diagnosis

The morphologic assessment of uterine leiomyosarcoma (LMS) may be challenging, and diagnostic immunohistochemical (IHC) analysis is currently lacking. We evaluated the genomic landscape of 167 uterine LMS by targeted next-generation sequencing (NGS) to identify common genomic alterations. IHC analyses corresponding to these genomic landmarks were applied to a test cohort of 16 uterine LMS, 6 smooth muscle tumors of uncertain malignant potential (STUMP), and 6 leiomyomas with NGS data and a validation cohort of 8 uterine LMS, 12 STUMP, 21 leiomyomas and leiomyoma variants, 7 low-grade endometrial stromal sarcomas, and 2 diagnostically challenging uterine smooth muscle tumors. IHC results were individually interpreted by 3 pathologists blinded to NGS data. Overall, 94% of LMS showed ≥1 genomic alteration involving TP53, RB1, ATRX, PTEN, CDKN2A, or MDM2, with 80% showing alterations in ≥2 of these genes. In the test cohort, an initial panel of p53, Rb, PTEN, and ATRX was applied, followed by a panel of DAXX, MTAP, and MDM2 in cases without abnormalities. Abnormal p53, Rb, PTEN, and ATRX IHC expression was seen in 75%, 88%, 44%, and 38% of LMS, respectively, in the test cohort. Two or more abnormal IHC results among these markers were seen in 81% of LMS. STUMPs demonstrated only 1 IHC abnormality involving these markers. No IHC abnormalities were seen in leiomyomas. In the validation cohort, abnormal p53, Rb, and PTEN IHC results were seen in LMS, whereas rare STUMP or leiomyomas with bizarre nuclei showed IHC abnormalities involving only 1 of the markers. Abnormalities in ≥2 markers were present in both diagnostically challenging smooth muscle tumors, confirming LMS. Concordance was excellent among pathologists in the interpretation of IHC (κ = 0.97) and between IHC and NGS results (κ = 0.941). Uterine LMS exhibit genomic landmark alterations for which IHC surrogates exist, and a diagnostic algorithm involving molecular-based IHC may aid in the evaluation of unusual uterine smooth muscle tumors.

Uterine sarcomas: clinical practice guidelines for diagnosis, treatment, and follow-up, by Spanish group for research on sarcomas (GEIS)

Uterine sarcomas are very infrequent and heterogeneous entities. Due to its rarity, pathological diagnosis, surgical management, and systemic treatment are challenging. Treatment decision process in these tumors should be taken in a multidisciplinary tumor board. Available evidence is low and, in many cases, based on case series or clinical trials in which these tumors have been included with other soft tissue sarcoma. In these guidelines, we have tried to summarize the most relevant evidence in the diagnosis, staging, pathological disparities, surgical management, systemic treatment, and follow-up of uterine sarcomas.

Uterine Inflammatory Myofibroblastic Tumors: Proposed Risk Stratification Model Using Integrated Clinicopathologic and Molecular Analysis

Inflammatory myofibroblastic tumor (IMT) of the uterus is a rare mesenchymal tumor with largely benign behavior; however, a small subset demonstrate aggressive behavior. While clinicopathologic features have been previously associated with aggressive behavior, these reports are based on small series, and these features are imperfect predictors of clinical behavior. IMTs are most commonly driven by ALK fusions, with additional pathogenic molecular alterations being reported only in rare examples of extrauterine IMTs. In this study, a series of 11 uterine IMTs, 5 of which demonstrated aggressive behavior, were evaluated for clinicopathologic variables and additionally subjected to capture-based next-generation sequencing with or without whole-transcriptome RNA sequencing. In the 6 IMTs without aggressive behavior, ALK fusions were the sole pathogenic alteration. In contrast, all 5 aggressive IMTs harbored pathogenic molecular alterations and numerous copy number changes in addition to ALK fusions, with the majority of the additional alterations present in the primary tumors. We combined our series with cases previously reported in the literature and performed statistical analyses to propose a novel clinicopathologic risk stratification score assigning 1 point each for: age above 45 years, size≥5 cm,≥4 mitotic figures per 10 high-power field, and infiltrative borders. No tumors with 0 points had an aggressive outcome, while 21% of tumors with 1 to 2 points and all tumors with ≥3 points had aggressive outcomes. We propose a 2-step classification model that first uses the clinicopathologic risk stratification score to identify low-risk and high-risk tumors, and recommend molecular testing to further classify intermediate-risk tumors.

Interactions between 14-3-3 Proteins and Actin Cytoskeleton and Its Regulation by microRNAs and Long Non-Coding RNAs in Cancer

14-3-3s are a family of structurally similar proteins that bind to phosphoserine or phosphothreonine residues, forming the central signaling hub that coordinates or integrates various cellular functions, thereby controlling many pathways important in cancer, cell motility, cell death, cytoskeletal remodeling, neuro-degenerative disorders and many more. Their targets are present in all cellular compartments, and when they bind to proteins they alter their subcellular localization, stability, and molecular interactions with other proteins. Changes in environmental conditions that result in altered homeostasis trigger the interaction between 14-3-3 and other proteins to retrieve or rescue homeostasis. In circumstances where these regulatory proteins are dysregulated, it leads to pathological conditions. Therefore, deeper understanding is needed on how 14-3-3 proteins bind, and how these proteins are regulated or modified. This will help to detect disease in early stages or design inhibitors to block certain pathways. Recently, more research has been devoted to identifying the role of MicroRNAs, and long non-coding RNAs, which play an important role in regulating gene expression. Although there are many reviews on the role of 14-3-3 proteins in cancer, they do not provide a holistic view of the changes in the cell, which is the focus of this review. The unique feature of the review is that it not only focuses on how the 14-3-3 subunits associate and dissociate with their binding and regulatory proteins, but also includes the role of micro-RNAs and long non-coding RNAs and how they regulate 14-3-3 isoforms. The highlight of the review is that it focuses on the role of 14-3-3, actin, actin binding proteins and Rho GTPases in cancer, and how this complex is important for cell migration and invasion. Finally, the reader is provided with super-resolution high-clarity images of each subunit of the 14-3-3 protein family, further depicting their distribution in HeLa cells to illustrate their interactions in a cancer cell.

Data Set for Reporting of Uterine Malignant and Potentially Malignant Mesenchymal Tumors: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

The International Collaboration on Cancer Reporting (ICCR) seeks to produce standardized, evidence-based protocols for the reporting of tumors with the aim of ensuring that all cancer reports generated worldwide will be of similar high quality and record the same elements. Herein, we describe the development of the data set for the reporting of uterine malignant and potentially malignant mesenchymal tumors by a panel of expert pathologists and a single clinician and provide the commentary and rationale for the inclusion of core and noncore elements. This data set, which incorporates the recent updates from the 5th edition of the World Health Organization Classification of Female Genital Tumors, addresses several subjects of debate including which mesenchymal tumors should be graded, how to document extent of invasion, mitotic counts, and the role of ancillary testing in tumor diagnosis and patient management. The inclusion of elements is evidence-based or based on consensus of the expert panel with clinical relevance being the guiding standard.

NTRK -Rearranged Uterine Sarcomas: Clinicopathologic Features of 15 Cases, Literature Review, and Risk Stratification

NTRK -rearranged uterine sarcomas are rare spindle cell neoplasms that typically arise in the uterine cervix of young women. Some tumors recur or metastasize, but features which predict behavior have not been identified to date. Distinguishing these tumors from morphologic mimics is significant because patients with advanced stage disease may be treated with TRK inhibitors. Herein, we present 15 cases of NTRK- rearranged uterine sarcomas, the largest series to date. Median patient age was 35 years (range: 16 to 61). The majority arose in the uterine cervix (n=14) and all but 2 were organ-confined at diagnosis. Tumors were composed of an infiltrative, fascicular proliferation of spindle cells and most showed mild-to-moderate cytologic atypia. All were pan-TRK positive by immunohistochemistry (13/13); S100 (11/13) and CD34 (6/10) were usually positive. RNA or DNA sequencing found NTRK1 (10/13) and NTRK3 (3/13) fusions with partners TPR , TPM3 , EML4 , TFG , SPECC1L , C16orf72 , and IRF2BP2 . Unusual morphology was seen in 2 tumors which were originally diagnosed as unclassifiable uterine sarcomas, 1 of which also harbored TP53 mutations. Follow up was available for 9 patients, of whom 3 died of disease. By incorporating outcome data of previously reported tumors, adverse prognostic features were identified, including a mitotic index ≥8 per 10 high-power fields, lymphovascular invasion, necrosis, and NTRK3 fusion. Patients with tumors which lacked any of these 4 features had an excellent prognosis. This study expands the morphologic spectrum of NTRK -rearranged uterine sarcomas and identifies features which can be used for risk stratification.

Endometrial Stromal Sarcomas With BCOR Internal Tandem Duplication and Variant BCOR/BCORL1 Rearrangements Resemble High-grade Endometrial Stromal Sarcomas With Recurrent CDK4 Pathway Alterations and MDM2 Amplifications

The distinction between low-grade and high-grade endometrial stromal sarcomas (LGESS, HGESS) is increasingly defined by genetics. Recently, variant genomic alterations involving BCOR or BCORL1 have been reported in endometrial stromal sarcoma (ESS), although it remains unclear whether these justify a diagnosis of LGESS or HGESS. In this study, we describe clinicopathologic and molecular features of ESS with such alterations to help clarify their classification in the spectrum of ESS. We collected a cohort of 13 ESS harboring variant alteration involving BCOR (6 with internal tandem duplication, 1 with EP300::BCOR fusion, 1 with BCOR::LPP fusion) and BCORL1 ( 4 with JAZF1::BCORL1 fusion, 1 with EPC1::BCORL1 fusion). The median patient age at primary diagnosis was 51 years (range: 18 to 70 y). Median tumor size at primary diagnosis was 9.3 cm (range: 4.5 to 21 cm), and extrauterine disease spread (stage IIIB-C) was present in 27%. The tumors were composed of round to spindled cells with cellularity and cytologic atypia ranging from mild to marked and a median mitotic count of 18/10 HPFs (range: 2 to 85/10 HPFs). At least focally myopermeative growth was noted in 8/8 assessable cases. Of 12 patients with follow-up data (median: 25 mo), 4 patients died of disease and 3 were alive with recurrent disease. Unsupervised hierarchical clustering of DNA methylation data together with a large cohort of uterine mesenchymal tumors that included YWHAE::NUTM2 and Z C3H7B::BCOR HGESS and molecularly confirmed LGESS revealed a common methylation signature for all ESS with variant BCOR and BCORL1 alterations and HGESS with YWHAE::NUTM2 and ZC3H7B::BCOR gene fusion. Copy number analysis revealed amplifications of CDK4 and MDM2 , as well as homozygous deletions of CDKN2A/B and NF1 in a subset of tumors. Our results indicate that ESS with BCOR internal tandem duplication and variant BCOR and BCORL1 rearrangements clinically and molecularly resemble conventional HGESS.

Adult NTRK-rearranged spindle cell neoplasms of the viscera: with an emphasis on rare locations and heterologous elements

NTRK-rearranged mesenchymal neoplasms mostly affect the soft tissues of pediatric patients. Given the responsiveness to selective NTRK inhibitors, it remains critical to identify those ultra-rare cases occurring in the viscera of adults. In five females and two males aged 18-53 years, we characterized visceral mesenchymal tumors harboring TPM3-NTRK1 [uterine cervix (N = 2), pleura, prostate], LMNA-NTRK1 (lung), SQSTM1-NTRK3 (heart), and NTRK3 rearrangement with unknown fusion partner (colon/mesocolon) with RNA sequencing, FISH, RT-PCR, and immunohistochemistry. The tumors exhibited spindled to ovoid/epithelioid or pleomorphic cells, often arranged in fascicles, and were low-to-intermediate-grade and high-grade in three and four cases, respectively. Keloid-like stromal collagen and perivascular hyalinization was noted in five. Adenosarcoma-like appearances were observed in two, manifesting frond-like protrusions in one cervical tumor and phyllodes-like architecture in the prostatic tumor. Abrupt high-grade transformation into pleomorphic liposarcoma was found in another cervical tumor, while the pleural tumor contained intermixed rhabdomyoblasts. Pan-TRK immunostaining was positive in all cases. All cases expressed CD34, while five were S100-positive. CDKN2A homozygous deletion with concomitant p16 loss occurred in 4/7. Whole-exome sequencing identified TP53 mutation (c.672+2T>C, involving a splice site, with concomitant protein loss) in a cervical sarcoma, limited to its heterologous liposarcomatous component. At least moderate pan-TRK immunoreactivity was present in varying proportions of potential pathologic mimics, with BCOR-positive sarcoma (56%, 5/9), undifferentiated uterine sarcoma (50%, 3/6), and spindle cell/sclerosing rhabdomyosarcoma (33%, 2/6) being among the most frequent. This underscored the unsatisfactory specificity of pan-TRK immunohistochemistry and warranted molecular confirmation in the diagnosis of adult NTRK-rearranged visceral mesenchymal neoplasms. The current report highlights the ever-expanding clinicopathologic and genetic spectrum of this entity by describing the unprecedented cardiac and pleural locations and heterologous differentiation, as well as the second NTRK-rearranged "prostatic stromal sarcoma," while substantiating CDKN2A deletion as a frequent occurrence.

Update on Uterine Mesenchymal Neoplasms

This review focuses on recent advances in epithelioid and myxoid uterine mesenchymal neoplasms, a category of tumors whereby diagnostic criteria have been rapidly evolving due to advances in molecular testing. Pertinent clinicopathological and molecular features are highlighted for perivascular epithelioid cell tumors, uterine tumors resembling ovarian sex cord tumors, BCOR/BCORL1-altered high-grade endometrial stromal sarcomas, and inflammatory myofibroblastic tumors. Novel developments in epithelioid and myxoid leiomyosarcomas are briefly discussed, and differential diagnoses with key diagnostic criteria are provided for morphologic mimickers.

High-grade Endometrial Stromal Sarcoma: Morphologic and Clinical Features, the Role of Immunohistochemistry and Fluorescence in Situ Hybridization in Diagnosis

Introduction. High-grade endometrial stromal sarcomas (HGESS) are rare malignant mesenchymal tumors of the uterus with aggressive poor clinical outcome, which frequently exhibit YWHAE::NUTM2 and ZC3H7B::BCOR fusions. In this study, we aimed to investigate HGESSs with YWHAE and BCOR translocations through our archive materials, and to identify morphological, immunohistochemical and molecular features of these tumors. We also assessed the diagnostic value of BCOR immunohistochemistry (IHC) in HGESSs, low-grade endometrial stromal sarcomas (LGESS) and uterine leiomyosarcomas. Methods. One hundred fifty-one uterine sarcomas diagnosed between 2000-2019 were reevaluated, and tumors of 39 patients with specific features were included in the study. Fluorescence in situ hybridization (FISH) studies using YWHAE and BCOR break-apart probes and BCOR IHC were performed. BCOR IHC was also performed in 20 leiomyosarcomas and 19 LGESSs. Results. In six HGESSs, translocations involving YWHAE or BCOR were detected. Five tumors showed high-grade morphology and revealed YWHAE translocation. One HGESS with myxoid morphology revealed BCOR translocation. In immunohistochemistry, three (3/4) YWHAE translocated HGESSs showed BCOR expression. However, the BCOR translocated HGESS was BCOR negative. The study showed that all LGESSs were immunohistochemically negative with BCOR. Although 15% (3/20) leiomyosarcomas reveal focal weak-moderate BCOR expression. Conclusion. BCOR IHC is a useful marker to distinguish LGESS from HGESS. A small percentage of uterine leiomyosarcomas reveal BCOR expression; however, it is not as diffuse and strong as in HGESSs. Strong and diffuse BCOR IHC expression is highly suggestive for HGESS. The diagnosis of HGESS should be supported by molecular studies such as FISH.

Clinicopathological and genomic characterization of BCORL1-driven high-grade endometrial stromal sarcomas

BCORL1 is a transcriptional corepressor homologous to BCOR. We describe 12 BCORL1-altered uterine sarcomas with striking resemblance to BCOR-altered endometrial stromal sarcoma (BCOR-ESS), including 5 with BCORL1 rearrangements (JAZF1-BCORL1, EP300-BCORL1, or internal BCORL1 rearrangement), 5 with inactivating BCORL1 mutations (T513fs*22, P600fs*1, R945*, R1196*, or R1265fs*4) and 2 with homozygous BCORL1 deletion. The median patient age was 57.5 years (range 33-79). An association with aggressive clinical behavior was identified. Diagnoses assigned prior to genomic testing varied: 7 tumors were previously diagnosed as ESS, 2 as high-grade uterine sarcomas, 2 as myxoid uterine leiomyosarcomas, and 1 as a uterine spindle cell neoplasm consistent with leiomyosarcoma. Tumors harbored frequent gelatinous, mucomyxoid-like appearance by gross examination and unique histology with morphological overlap with BCOR-ESS. Key microscopic features included (1) a spindle cell appearance, most often with at least focal myxoid stroma, (2) variable amounts of hypocellular fibromyxoid spindle areas with lower grade atypia and/or (3) variable amounts of epithelioid areas with higher grade atypia. Specifically, spindle and epithelioid components were present in 100 and 75% of sarcomas, respectively; myxoid stroma was identified in 83%, collagen plaques or fibrosis in 50%, and high-grade nuclear atypia was present in 42%. Like BCOR-ESS, 50% of BCORL1-altered sarcomas exhibited CDK4 amplification or CDKN2A loss. In contrast, 33% harbored NF1 alterations, while 25% had other alterations in the NF2-mTOR pathway, expanding potential therapeutic targets. In conclusion, inactivating BCORL1 genomic alterations may define a distinct subset of high-grade endometrial stromal sarcomas with biological overlap with BCOR-ESS, both of which may mimic myxoid leiomyosarcomas.

Protracted clinical course of an AFF1 fusion positive uterine smooth muscle tumor causing diagnostic confusion over a course of 15 years

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Histologic diagnostic criteria alone for uterine smooth muscle tumors lacks robust prognostication.

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Molecular/genetic techniques should be advocated to further investigate unusual case presentations.

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Novel identification of a PTP4A2-AFF1 genetic fusion was identified.

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The novel PTP4A2-AFF1 genetic fusion may have further diagnostic prognostic, and therapeutic implications.