Ewing's sarcoma (ES) and desmoplastic small round cell tumors (DSRCT) are small round blue cell tumors driven by an N-terminal containing EWS translocation.
We identified specific microRNA expression patterns which distinguish medulloblastoma differing in histotypes (anaplastic, classic and desmoplastic), in molecular features (ErbB2 or c-Myc overexpressing tumors) and in disease-risk stratification.
An activating point mutation of the BRAF oncogene has been identified in a high proportion of conventional cutaneous melanomas, but its frequency in the desmoplastic subtype is not known.
Pancreatic ductal adenocarcinoma (PDAC) commonly contains a mutation in K-Ras(G12D) and is characterized by a desmoplastic reaction composed of deregulated, proliferating cells embedded in an abnormal extracellular matrix (ECM).
Separate analysis of morphologically heterogeneous tumor areas in four mixed desmoplastic malignant melanomas displayed no difference in mutation status and RET G691 status.
Tumour growth pattern (expansive/infiltrative/diffuse) and tumour stroma (desmoplastic common-type versus keloid-like) showed a statistically significant association with tumour cell dissociation and with beta-catenin translocation.
We found that neoplastic cells expressed beta-tubulin in 91% of the tumors (23 classic and 10 desmoplastic), synaptophysin in 75% (19 classic and 8 desmoplastic), S-Ag in 44% (11 classic and 5 desmoplastic), and GFAP in 11% of medulloblastomas (2 classic and 2 desmoplastic).
We found that neoplastic cells expressed beta-tubulin in 91% of the tumors (23 classic and 10 desmoplastic), synaptophysin in 75% (19 classic and 8 desmoplastic), S-Ag in 44% (11 classic and 5 desmoplastic), and GFAP in 11% of medulloblastomas (2 classic and 2 desmoplastic).
Indeed, we observed germline microdeletions/duplications of regions encompassing cancer-related genes in 50% of patients undergoing array-CGH: EIF3H duplication in a patient with infantile desmoplastic astrocytoma and low-grade Glioma; SLFN11 deletion, SOX4 duplication, and PARK2 partial deletion in three neuroblastoma patients; a PTPRD partial deletion in a child diagnosed with glioblastoma multiforme.
Nine of the 28 cases were variants in the ATM gene and were found to share similar histologic characteristics; all had tumor cells with low nuclear grade, absent tumor infiltrating lymphocytes, as well as a marked desmoplastic response.
Surgical specimens from 36 medulloblastomas (25 classic and 11 desmoplastic) were studied by peroxidase-antiperoxidase (PAP) immunohistochemistry with antibodies against the class III beta-tubulin isotype (beta-tubulin), synaptophysin, retinal S-antigen (S-Ag), and glial fibrillary acidic protein (GFAP).
The breakpoints on 22q were in all 5 cases cytogenetically indistinguishable from those seen in Ewing's sarcoma with t(11;22), clear-cell sarcoma with t(12;22), and desmoplastic small round cell tumors with t(11;22).