JHUEM-1

JHUEM-1 is a patient-derived endometrial cancer cell line established from the primary, malignant ascites fluid of a patient with advanced stage, high-grade endometrioid endometrial carcinoma (EEC). Unlike traditional models, it was developed and characterized using modern, well-annotated protocols, ensuring its genetic and phenotypic fidelity to the original patient tumor. This places it among a newer generation of highly representative in vitro models. Its most significant defining feature is the presence of a pathogenic, ultra-mutator mutation in the DNA polymerase epsilon exonuclease domain (POLE gene, P286R variant). This places JHUEM-1 within the clinically important POLE-ultramutated (POLEmut) molecular subgroup of endometrial cancer, a subtype characterized by an exceptionally high tumor mutational burden (TMB) and a generally favorable prognosis when detected early.

JHUEM-1 cells exhibit an epithelial morphology. Their defining molecular characteristic is the heterozygous driver mutation in POLE (c.857C>G, p.Pro286Arg), which results in defective proofreading during DNA replication. This leads to an extraordinarily high somatic mutation rate (TMB-H) and the generation of a vast repertoire of potential neoantigens. Consistent with its POLE mutation, the cell line is microsatellite stable (MSS) and estrogen receptor (ER) positive, reflecting a distinct biology separate from the microsatellite instability-high (MSI-H) or copy-number high (serous-like) subtypes. JHUEM-1 is tumorigenic in immunocompromised mice, forming xenografts, and has undergone extensive genomic and transcriptomic profiling.