The genomic landscape of the Ewing Sarcoma family of tumors reveals recurrent STAG2 mutation.

The Ewing sarcoma family of tumors (EFT) is a group of highly malignant small round blue cell tumors occurring in children and young adults. We report here the largest genomic survey to date of 101 EFT (65 tumors and 36 cell lines). Using a combination of whole genome sequencing and targeted sequencing approaches, we discover that EFT has a very low mutational burden (0.15 mutations/Mb) but frequent deleterious mutations in the cohesin complex subunit STAG2 (21.5% tumors, 44.4% cell lines), homozygous deletion of CDKN2A (13.8% and 50%) and mutations of TP53 (6.2% and 71.9%). We additionally note an increased prevalence of the BRCA2 K3326X polymorphism in EFT patient samples (7.3%) compared …

Unusual Intranuclear Inclusions in Malignant Fibrous Histiocytoma: Presence in Primary Tumor

We describe previously unreported intranuclear inclusions in 2 cases of malignant fibrous histiocytoma. The inclusions were found in 2-10% of the tumor cells removed from the patients and in 2-10% of the cells examined in tumor tissue xenotransplanted in nude mice. By stereo electron microscopy the inclusions are closely packed undulating fibrils 18-23 nm in diameter. They are sometimes associated with fibrillary bodies. They closely resemble the inclusions reported in some animals inoculated with serum from patients with non-A non-B hepatitis; however, their nature at present is unknown.

Translocation (11;22) in small cell osteosarcoma

Scanning electron microscopic evidence for neural differentiation in Ewing's sarcoma cell lines.

A number of recent studies have suggested a relationship between Ewing's sarcoma (ES) and other small round cell tumours of childhood such as peripheral neuroepithelioma (PN). We report scanning electron microscopic studies on the character of induced neural differentiation in ES, neuroblastoma, PN, osteosarcoma and colon carcinoma. We found evidence of neural differentiation in both neural lines and in one of two Ewing's lines before treatment. After differentiation, both Ewing's and neural lines developed neuritic processes with varicosities and little arborization, except for the initially undifferentiated Ewing's line (A4573) which displayed extensive lateral sprouting from neuritic pro…