ERG and FLI1 are useful immunohistochemical markers in phosphaturic mesenchymal tumors

Abstract

Phosphaturic mesenchymal tumors (PMT) are the most common cause of tumor-induced osteomalacia (TIO) related to mesenchymal neoplasms. The lineage of differentiation of PMTs has not been elucidated in existing literature. Fourteen cases of PMT were analyzed for this study to elucidate its lineage. We used vascular and/or lymphatic endothelial markers for the immunohistochemical analysis, which included CD31, CD34, factor VIII-related antigen, podoplanin, Freund's leukemia integration site 1 (FLI1), and avian v-ets erythroblastosis virus E26 oncogene homolog (ERG). FLI1 and ERG were stained in all cases with proportion of immunopositive tumor cells largely more than 50 %; staining intensity was moderate or strong for both FLI1 and ERG. The tumor cells were stained with CD31 and/or CD34, with significantly less staining than observed for FLI1 and ERG. The tumor cells were completely immunonegative for factor VIII-related antigen and podoplanin. FLI1 and ERG are known to have considerable specificity to endothelial cells; ERG is more widely equipped in surgical pathology laboratories than FLI1. We concluded that ERG (or FLI1 if available) is useful marker for the diagnosis of PMT, and that PMTs may have an endothelial cell lineage.

Novel EWSR1-SMAD3 Gene Fusions in a Group of Acral Fibroblastic Spindle Cell Neoplasms

“…11 Another interesting finding is that ERG immunoreactivity has also been reported in phosphaturic mesenchymal tumors, with variable positive rates (38–100%). 12–14 Similar to our cohort, an upregulated FN1 mRNA expression is also seen in a subset of phosphaturic mesenchymal tumors with FN1 - FGFR1/FGF1 fusions, 15 suggesting a potential correlation between the FN1 and ERG transcriptional co-activation.…”

Tumeurs des tissus mous avec fusion du gène FN1 (Fibronectine 1)

“…Des remaniements pseudoanévrysmatiques avec la présence d'ostéoclastes, des territoires adipeux et ponctuellement une matrice chondroïde ou ossifiée s'associent fréquemment aux territoires fusiformes. En immunohistochimie, on note une expression fréquente de CD56, ERG, SSTR2A, SATB2, FGF23 [15][16][17][18]. Cependant, elle n'est pas spécifique ni indispensable au diagnostic.…”

Phosphaturic mesenchymal tumor in right thigh: 2 cases report and literature review

“… 33 In addition, tumor cells can also express D2-40, SSTR2A, ERG and FLI1, CD56, SMA and SATB2, etc. 15 , 32 , 34 - 36 Although ultrastructurally similar to neuroendocrine tumor cells, PMTs rarely express markers such as S-100, NSE, syn, and CgA. 11 Houang et al believed that FGF23 and SSTR2A were particularly sensitive but not specific for the diagnosis of PMT.…”