👤 Alphonse Charbel

This review examines the rapidly evolving landscape of myeloproliferative hypereosinophilic syndromes (HES) and related neoplasms. We aim to synthesize current understanding of their diverse molecular drivers, evaluate the efficacy of established and novel targeted therapies, and identify critical research gaps. The goal is to provide a clinically relevant update on how molecular precision is reshaping the diagnosis and management of these rare, often aggressive hematologic malignancies beyond the established standard of imatinib. The field has moved beyond generic HES diagnoses to a molecularly defined classification. While imatinib remains the standard for The management of myeloproliferative HES has transitioned from empirical therapy to a precision medicine paradigm. Early comprehensive molecular profiling is essential to guide therapy selection. While imatinib remains a cornerstone for select patients, novel agents like pemigatinib and avapritinib have filled critical therapeutic gaps. Future progress depends on the routine integration of comprehensive next-generation sequencing, the validation of minimal residual disease monitoring to guide therapy de-escalation, and international collaboration to conduct innovative trials for these rare patient populations. Show less

Uterine mesenchymal tumours harboring KAT6B/A::KANSL1 gene fusions typically exhibit histological and immunophenotypic overlap with endometrial stromal and smooth muscle tumours. To date it remains uncertain whether such neoplasms should be regarded as variants of smooth muscle or endometrial stromal neoplasm, or if they constitute a distinct tumour type. In this study we investigated DNA methylation patterns and copy number variations (CNVs) in a series of uterine tumours harboring KAT6B/A::KANSL1 gene fusions in comparison to other mesenchymal neoplasms of the gynecological tract. Unsupervised hierarchical clustering and t-SNE analysis of DNA methylation data (Illumina EPIC array) identified a distinct cluster for 8/13 KAT6B/A::KANSL1 tumours (herein referred to as core cluster). The other 5 tumours (herein referred to as outliers) did not assign to the core cluster but clustered near various other tumour types. CNV analysis did not identify significant alterations in the core cluster. In contrast, various alterations, including deletions at the CDKN2A/B and NF1 loci were identified in the outlier group. Analysis of the DNA methylation clusters in relation to histological features revealed that while tumours in the core KAT6B/A::KANSL1 cluster were histologically bland, outlier tumours frequently exhibited "high-grade" histologic features in the form of significant nuclear atypia, increased mitotic activity and necrosis. Three of the five patients with outlier tumours died from their disease while clinical follow-up in the remaining two patients was limited (less than 12 months). In comparison, none of the 7 out of 8 patients with tumors in the core KAT6B/A::KANSL1 sarcoma cluster, where follow-up was available, died from disease. Furthermore, only 1 out of 7 patients recurred (mean follow-up of 30 months). In conclusion, KAT6B/A::KANSL1 uterine sarcoma is a molecularly unique type of uterine tumour that should be recognized as a distinct entity. These tumors typically exhibit low-grade histologic features but are occasionally morphologically high-grade; the latter have a DNA methylation profile different from the typical low-grade neoplasms and may be associated with aggressive behaviour. Show less