A Novel EPC1::KDM2B Fusion in High-grade Endometrial Stromal Sarcoma.

The spectrum of endometrial stromal sarcoma (ESS) has expanded substantially since the publication of the most recent World Health Organisation (WHO) Classification of Female Genital Tumours and the advent of widely available genomic testing. We describe a uterine mesenchymal tumor harboring a novel EPC1::KDM2B fusion, best classified within the umbrella of high-grade endometrial stromal sarcoma (HGESS). This tumor was composed of a uniform population of spindled cells with some myxoid stroma, a mitotic rate of up to 21/10 high-power fields, and a largely pushing margin with focal vascular invasion. Immunohistochemistry showed strong and diffuse cyclin D1 positivity while CD10, WT1, DOG1, CD117, CD34, CD99, S100, MelanA, SMA, desmin, and h-caldesmon were negative. The tumor was confined to the uterus and no recurrence has been detected thus far, albeit with a short follow-up interval of 9 mo.

Tumour budding is associated with hypoxia at the advancing front of colorectal cancer.

AIMS: The tumour budding ability to predict cancer progression is felt to be worthy of investigation with regard to its biological properties. This study was aimed at evaluating the role of hypoxia and microvascularization in the morphogenesis of tumour budding in colorectal carcinoma. METHODS AND RESULTS: The immunohistochemical expression of hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase IX in cancer cells and CD105 in carcinoma-induced microvascularization were assessed in 479 colorectal cancers. Furthermore, MET proto-oncogene, receptor tyrosine kinase (MET) gene amplification was searched using fluorescence in-situ hybridization (FISH). Carbonic anhydrase IX and HIF-1α overall scores differed significantly in low- compared to high-grade tumour budding cancers (P < 0.001), both in pT1 and in pT2-4 tumours. Intratumour analysis of budding foci showed a striking absence of carbonic anhydrase IX immunostain in detaching cells with respect to the surrounding microsectors. The mean microvessel density values were significantly higher in the low- compared to the high-grade tumour budding groups (P < 0.001). A similar copy number of MET gene was detected in the two groups. CONCLUSIONS: Our study shows that tumour budding is associated with hypoxia induced by hypovascularization at the advancing front of colorectal cancer and that budding cells express a HIF-1α-mediated hypoxic tumour phenotype. MET gene amplification is not related to tumour budding morphogenesis.