High-Grade Early-Onset Prostate Cancer: Assessment of TMPRSS2::ERG-Negative Tumors Suggests Low Frequency of Germline Alterations and a Pathogenic Role for HOXB13.

Early onset prostate cancer (EOPC; defined herein as prostate cancer [PCa] affecting men ≤ 55 years-old) tends to show low histologic grade, likely representing early detection of indolent tumors that would otherwise be diagnosed later in life. A small subset of EOPC exhibits Gleason scores consistent with high-risk disease (Grade Groups 4 to 5; high-grade EOPC [HG-EOPC] hereafter). In this study, we assess the clinicopathologic features of HG-EOPC, with genomic analysis of ERG-negative cases.

MUC4-positive Fibroblastoma: A Distinctive Hyalinized Spindle Cell Neoplasm With Aberrant Nuclear Beta-catenin Expression and Frequent Biallelic Inactivation of APC.

Among soft tissue tumors, MUC4 is expressed in low-grade fibromyxoid sarcoma and sclerosing epithelioid fibrosarcoma, and is regarded as a specific and sensitive marker for these malignant entities. These tumors are driven by oncogenic fusions involving FUS or EWSR1 as a 5' partner and CREB3L1 or CREB3L2 as a 3' partner. In this study, we describe the clinicopathologic and molecular features of a distinctive fibroblastic soft tissue neoplasm characterized by consistent co-expression of MUC4 and beta-catenin, and frequent underlying APC inactivation without evidence of EWSR1 or FUS rearrangements.

Genetic correlates of malignancy in TFE3-rearranged PEComa: a series of 14 cases.

Aims: Perivascular epithelioid cell tumours (PEComas) show variable smooth muscle and melanocytic differentiation and mostly harbour mTOR pathway activation via TSC2 inactivation. Five-10% of sporadic PEComas instead harbour fusions involving TFE3, an vmTOR pathway target. Malignancy in TSC2/1-inactivated PEComa correlates with TP53, RB1 or ATRX inactivation.

Antitumor Activity of Vebreltinib and Characterization of Clinicogenomic Features in Solid Tumors with MET Rearrangements.

Unlabelled: Oncogenic translocations involving the MET gene have been reported in several cancer types, but detailed clinicogenomic characterization of these cancers is not well defined. In addition, prospective clinical trials evaluating the antitumor activity of MET inhibitors in MET rearrangement-positive cancers are limited. In this study, in a pan-cancer analysis of >46,000 solid tumors with comprehensive genomic profiling, we identified oncogenic MET rearrangements in ∼0.

Malignant Giant Cell Tumor of Bone: A Clinicopathologic Series of 28 Cases Highlighting Genetic Differences Compared With Conventional, Atypical, and Metastasizing Conventional Tumors.

Giant cell tumors of bone are locally aggressive, frequently harbor H3F3A p.G34W mutations, and rarely undergo malignant transformation. The pathogenesis of malignant transformation remains incompletely characterized.

Pan-Cancer Analysis of Oncogenic MET Fusions Reveals Distinct Pathogenomic Subsets with Differential Sensitivity to MET-Targeted Therapy.

Unlabelled: MET fusions (MET-F) are oncogenic drivers that remain poorly characterized. Analysis of 56 MET-F-positive tumors from an institutional cohort of 91,119 patients (79,864 DNA sequencing plus 11,255 RNA sequencing) uncovered two forms of MET-F pathobiology. The first group featured 5' partners with homodimerization domains fused in-frame with the MET tyrosine kinase domain, primarily originated from translocations, frequently excluded MET exon 14, mediated oncogenesis through cytoplasmic aggregation and constitutive activation, and were markedly sensitive to MET tyrosine kinase inhibitors (TKI) in preclinical models and patients with lung cancer.

BRAF Gene Fusions in Melanoma: First Kinase Domain Duplication, New Fusion Partners, and Clinical Outcomes.

BRAF gene fusions have been well-described in Spitzoid melanocytic lesions but can also occur uncommonly in conventional melanomas. Here we report a series of 17 melanomas harboring BRAF gene fusions as their putative primary genetic driver. All but one of these tumors occurred in adults (age range 13 to 96) with a relatively even sex distribution (41% female) and a broad distribution of anatomic sites.

Genomic Profiling of Cardiac Angiosarcoma Reveals Novel Targetable KDR Variants, Recurrent MED12 Mutations, and a High Burden of Germline POT1 Alterations.

Purpose: Cardiac angiosarcoma is a rare, aggressive malignancy with limited treatment options. Both sporadic and familial cases occur, with recent links to germline POT1 mutations. The genomic landscape of this disease is poorly understood.

Clear Cell Stromal Tumor of the Lung: Clinicopathologic, Immunohistochemical, and Molecular Characterization of Eight Cases.

Clear cell stromal tumor is a recently described mesenchymal neoplasm of the lung, characterized by spindle cells with variably clear-to-pale eosinophilic cytoplasm and prominent vascularity, as well as a recurrent YAP1::TFE3 gene fusion in most cases. Diagnosis can be challenging given its rarity and the lack of supportive immunohistochemical (IHC) markers aside from TFE3. To date, less than 20 cases have been reported, and data on clinical behavior are also limited.

Preclinical evaluation of targeted therapies for central nervous system metastases.

The central nervous system (CNS) represents a site of sanctuary for many metastatic tumors when systemic therapies that control the primary tumor cannot effectively penetrate intracranial lesions. Non-small cell lung cancers (NSCLCs) are the most likely of all neoplasms to metastasize to the brain, with up to 60% of patients developing CNS metastases during the disease process. Targeted therapies such as tyrosine kinase inhibitors (TKIs) have helped reduce lung cancer mortality but vary considerably in their capacity to control CNS metastases.

Epithelioid Fibrous Histiocytoma Is on a Continuum With Superficial ALK -rearranged Myxoid Spindle Cell Neoplasm : A Clinicopathologic Series of 35 Cases Including Alternate RET and NTRK3 Fusions.

Anaplastic lymphoma kinase ( ALK ) rearrangements drive most examples of epithelioid fibrous histiocytoma (EFH) and have been reported in an emerging family of receptor tyrosine kinase (RTK) fusion-positive mesenchymal neoplasms, including superficial ones described under the rubric of "superficial ALK -rearranged myxoid spindle cell neoplasm" (SAMS). Here, we describe 35 superficial tumors with SAMS morphology, which occurred in 18 females (51%) and 17 males at a median age at presentation of 39 years (range: 6 to 82 y). Most tumors occurred on the lower extremity (25 tumors; 71%), followed by upper extremity (5; 14%), trunk (3; 9%), and face (2; 6%).

Combination of MDM2 and Targeted Kinase Inhibitors Results in Prolonged Tumor Control in Lung Adenocarcinomas With Oncogenic Tyrosine Kinase Drivers and Amplification.

Purpose: MDM2, a negative regulator of the TP53 tumor suppressor, is oncogenic when amplified. amplification (MDM2amp) is mutually exclusive with mutation and is seen in 6% of patients with lung adenocarcinoma (LUAD), with significant enrichment in subsets with receptor tyrosine kinase (RTK) driver alterations. Recent studies have shown synergistic activity of MDM2 and MEK inhibition in patient-derived LUAD models with MDM2amp and RTK driver alterations.

HER2 Antibody-Drug Conjugates Are Active against Desmoplastic Small Round Cell Tumor.

Purpose: Desmoplastic small round cell tumor (DSRCT) is a rare but highly aggressive soft tissue sarcoma that arises in the abdominopelvic cavity of young males. Since the discovery of EWSR1::WT1 fusion as the driver of DSRCT, no actionable genomic alterations have been identified, limiting disease management to a combination of surgery, chemotherapy, and radiation, with very poor outcomes. Herein, we evaluated ERBB2/HER2 expression in DSRCT as a therapeutic target.

Myxoid Inflammatory Myofibroblastic Sarcoma: Clinicopathologic Analysis of 25 Cases of a Distinctive Sarcoma With Deceptively Bland Morphology and Aggressive Clinical Behavior.

The number of recognized sarcoma types harboring targetable molecular alterations continues to increase. Here we present 25 examples of a distinctive myofibroblastic tumor, provisionally termed "myxoid inflammatory myofibroblastic sarcoma," which might be related to inflammatory myofibroblastic tumor, and which occurred in 13 males (52%) and 12 females at a median age of 37 years (range: 7 to 79 years). Primary tumor sites were peritoneum (18 patients; 72%), paratesticular (2; 8%), chest wall (1), upper extremity (1), esophagus (1), retroperitoneum (1), and uterus (1).

A visual-language foundation model for computational pathology.

The accelerated adoption of digital pathology and advances in deep learning have enabled the development of robust models for various pathology tasks across a diverse array of diseases and patient cohorts. However, model training is often difficult due to label scarcity in the medical domain, and a model's usage is limited by the specific task and disease for which it is trained. Additionally, most models in histopathology leverage only image data, a stark contrast to how humans teach each other and reason about histopathologic entities.

Prognostic and predictive biomarkers in non-small cell lung carcinoma.

Lung cancer is the most common cause of cancer-related deaths globally, with the highest mortality rates among both men and women. Most lung cancers are diagnosed at late stages, necessitating systemic therapy. Modern clinical management of lung cancer relies heavily upon application of biomarkers, which guide the selection of systemic treatment.

Prevalence and Therapeutic Targeting of High-Level ERBB2 Amplification in NSCLC.

Introduction: ERBB2 amplification in lung cancer remains poorly characterized. HER2 (encoded by ERBB2) is a transmembrane tyrosine kinase capable of ligand-independent dimerization and signaling when overexpressed, and a common cause of HER2 overexpression is ERBB2 amplification. Here, we evaluated the clinicopathologic and genomic characteristics of ERBB2-amplified NSCLC and explored a HER2 antibody-drug conjugate (ADC) therapeutic strategy.

Vepafestinib is a pharmacologically advanced RET-selective inhibitor with high CNS penetration and inhibitory activity against RET solvent front mutations.

RET receptor tyrosine kinase is activated in various cancers (lung, thyroid, colon and pancreatic, among others) through oncogenic fusions or gain-of-function single-nucleotide variants. Small-molecule RET kinase inhibitors became standard-of-care therapy for advanced malignancies driven by RET. The therapeutic benefit of RET inhibitors is limited, however, by acquired mutations in the drug target as well as brain metastasis, presumably due to inadequate brain penetration.

Infantile Sinonasal Myxoma Is Clinically and Genetically Distinct From Other Myxomas of the Craniofacial Bones and From Desmoid Fibromatosis.

Sinonasal myxomas are rare benign tumors of the maxillary bone and sinus. There is published evidence that sinonasal myxomas occurring in children up to 3 years of age ("infantile sinonasal myxomas") are clinically distinctive and harbor Wnt signaling pathway alterations. Here, we characterized 16 infantile sinonasal myxomas and compared them to 19 maxillary myxomas and 11 mandibular myxomas in older patients.

Combination Therapy With MDM2 and MEK Inhibitors Is Effective in Patient-Derived Models of Lung Adenocarcinoma With Concurrent Oncogenic Drivers and MDM2 Amplification.

Introduction: Although targeted therapies have revolutionized the therapeutic landscape of lung adenocarcinomas (LUADs), disease progression on single-agent targeted therapy against known oncogenic drivers is common, and therapeutic options after disease progression are limited. In patients with MDM2 amplification (MDM2amp) and a concurrent oncogenic driver alteration, we hypothesized that targeting of the tumor-suppressor pathway (by means of restoration of p53 using MDM2 inhibition) and simultaneous targeting of co-occurring MAPK oncogenic pathway might represent a more durably effective therapeutic strategy.

Methods: We evaluated genomic next-generation sequencing data using the Memorial Sloan Kettering Cancer Center-Integrated Mutation Profiling of Actionable Cancer Targets platform to nominate potential targets for combination therapy in LUAD.