Genes, Chromosomes & Cancer最新文献

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare and clinically aggressive variant of inflammatory myofibroblastic tumor (IMT). It typically presents in children and young adults, often affecting the abdominal cavity. It is characterized by the presence of plump, polyhedral, and epithelioid cells, and a distinctive nuclear or perinuclear ALK staining on immunohistochemistry. Various ALK fusion partners have been identified in EIMS, including RANBP2, RRBP1, EML4, and VCL. In this report, we present four cases of EIMS involving the abdominal cavity, including the first case with a CLTC::ALK fusion, which has previously been associated only with nonaggressive IMT.

Chromosomal translocations are key events in cancer, driving oncogenesis by disrupting and deregulating critical genes. While specific tumor-associated translocations are well studied, the frequencies and distributions of most remain unknown. Additionally, the role of chromosomal reshuffling in translocations has received little attention. This study presents data on the chromosomal involvement in 59 251 translocations reported in 58 tumor entities, including both benign and malignant tumors. Unlike studies focusing on tumor-specific abnormalities identified at the chromosome band level, this study examines translocations at the chromosomal level, offering a novel perspective on their distribution. This broader approach aims to uncover patterns that do not emerge or are disregarded in studies limited to tumor-specific aberrations. The resulting dataset provides a novel resource for deepening our understanding of the chromosomal origins of translocations in neoplasia. Comparisons of translocation frequency distributions among tumor types, when excluding the characteristic tumor-associated translocations, revealed that the patterns of chromosomal involvement in translocations are largely unique to each tumor entity. Statistical analyses of 241 pairwise comparisons of translocation spectra within hematologic disorders, solid tumors, and between groups of hematologic malignancies and both benign and malignant solid tumors showed insignificant/very weak associations (R² ≤ 0.3) in 98% of the comparisons. The findings hence demonstrate that different tumor types are characterized by distinct chromosomal translocation signatures, strongly suggesting that most translocations encountered in tumor cells are not merely random events. Consequently, our study highlights the potential of rare translocations to serve as indicators of disease-specific processes.

Pediatric fibroblastic, myofibroblastic, and myoid tumors encompass several entities, many with characteristic gene fusions that are now emerging as molecularly defined tumor groups. Here, we present two cases of spindle cell neoplasms with novel ACTB::FER promoter swap fusions. Both tumors presented in the extremities of pediatric patients (9-year-old and 6-year-old females) as superficial skin nodules with slow growth. Histologically, both tumors showed monomorphic spindle cell proliferation in short fascicles, but without significantly increased mitotic activity, high-grade atypia, or necrosis. Both cases showed diffuse positivity for SMA with patchy desmin expression. RNA sequencing confirmed fusion breakpoints, revealing transcriptional upregulation of FER. Neither patient has had evidence of interval growth or recurrence to date. While the biological significance of ACTB::FER fusions remains unclear, their recurrence and the absence of other clear oncogenic drivers suggest a distinct molecular pathway that may define a novel entity. Fusions of ACTB and FER genes with different partners have been observed in rare aggressive mesenchymal tumors; however, the ACTB::FER promoter swap fusion is currently unrecognized in soft tissue tumors. We report the first two cases of soft tissue tumors harboring ACTB::FER fusions and expand the molecular spectrum of mesenchymal tumors with kinase gene alterations. Further, we highlight the importance of target-agnostic approaches for the detection of rare kinase fusions, which may not be included on targeted next-generation sequencing panels.

Burkitt lymphoma (BL) is an aggressive germinal center B-cell-derived malignancy. Historically, sporadic, endemic, and immunodeficiency-associated variants were distinguished, which differ in the frequency of Epstein–Barr virus (EBV) positivity. Aiming to identify subgroups based on DNA methylation patterns, we here profiled 96 BL cases, 17 BL cell lines, and six EBV-transformed lymphoblastoid cell lines using Illumina BeadChip arrays. DNA methylation analyses clustered the cases into four subgroups: two containing mostly EBV-positive cases (BL-mC1, BL-mC2) and two containing mostly EBV-negative cases (BL-mC3, BL-mC4). The subgroups BL-mC1/2, enriched for EBV-positive cases, showed increased DNA methylation, epigenetic age, and, in part, proliferation history compared to BL-mC3/4. CpGs hypermethylated in EBV-positive BLs were enriched for polycomb repressive complex 2 marks, while the CpGs hypomethylated in EBV-negative BLs were linked to, for example, B-cell receptor signaling. EBV-associated hypermethylation affected regulatory regions of genes frequently mutated in BL (e.g., CCND3, TP53) and impacted superenhancers. This finding suggests that hypermethylation may compensate for the lower mutational burden of pathogenic drivers in EBV-positive BLs. Though minor, significant differences were also observed between EBV-positive endemic and sporadic cases (e.g., at the SOX11 and RUNX1 loci). Our findings suggest that EBV status, rather than epidemiological variants, drives the DNA methylation-based subgrouping of BL.

EGFR-kinase-domain duplication (KDD) has been reported in Infantile fibrosarcoma-like myofibroblastic tumors and cellular mesoblastic nephroma. We report a pulmonary neoplasm with EGFR-(KDD) and infantile fibrosarcoma-like histologic features in a female infant with an unusual clinical and histologic evolution, characterized by persistent disease with morphologic features of Congenital Peribronchial Myofibroblastic Tumor (CPMT) after chemotherapy and targeted therapy. The CPMT morphology with EGFR-KDD in the post-therapy specimen might be an evolution induced by the treatment, which suggests the hypothesis that CPMT is part of the morphologic spectrum of infantile fibrosarcoma/cellular mesoblastic nephroma.