Real-time quantitative polymerase chain reaction testing confirmed the presence of ASPSCR1-TFE3 fusion transcripts, characteristic of the translocation t(X;17) p(11.2;q25) observed in ASPS.
TFE3 regulates both Golgi and lysosomal homeostasis and is rearranged in renal cell carcinoma (RCC), alveolar soft part sarcoma, epithelioid hemangioendothelioma, and perivascular epitheloid cell tumors (PEComas).
Following identification of an index case of ASPS with a novel TFE3 fusion partner, we performed a retrospective review to determine whether this represents an isolated event.
Alveolar soft part sarcoma (ASPS) is a rare malignancy with high rates of metastasis at presentation, defined by an unclear cellular origin and a unique unbalanced ASPSCR1-TFE3 translocation (der(17)t(X:17)(p11:q25)).<sup>1</sup> ASPS is insensitive to chemotherapy and has been reported to involve the bladder only twice in the pediatric literature; once as a primary malignancy,<sup>2</sup> and once as a secondary malignancy after cytotoxic chemotherapy.<sup>3</sup> Herein, we report the third case of pediatric bladder ASPS in a female patient who received cytotoxic chemotherapy for low-risk neuroblastoma.
We here report an interesting and challenging case of malignant PEComa that showed transcription factor E3 (TFE3) protein expression and rearrangement, paucity of muscle and melanocytic marker expression, and morphologically mimicked alveolar soft part sarcoma.
According to European Organization for Research and Treatment of Cancer (EORTC) efficacy criteria for soft tissue sarcoma, our study demonstrated that crizotinib has activity in TFE3 rearranged ASPS MET+ patients.
Eleven cases with an initial diagnosis of ASPS at female genital tract sites were evaluated for their morphologic features and immunoprofile using a panel of antibodies (TFE3, HMB45, melan-A, smooth muscle actin, desmin, and h-Caldesmon).
TFE3 staining and knowledge of its microscopic characteristics would facilitate earlier diagnosis: Early diagnosis with a multidisciplinary, multimodal approach to treatment is required to achieve extended disease-free survival in patients with brain metastatic ASPS.
Furthermore, among neoplasms with the SFPQ-TFE3, NONO-TFE3, DVL2-TFE3, and ASPL-TFE3 gene fusions, the RCCs are almost always PAX8 positive, cathepsin K negative by immunohistochemistry, whereas the mesenchymal counterparts (Xp11 translocation PEComas, melanotic Xp11 translocation renal cancers, and alveolar soft part sarcoma) are PAX8 negative, cathepsin K positive.
It is characterized by a specific chromosomal alteration, der(17)t(X:17)(p11:q25), resulting in fusion of the transcription factor E3 (TFE3) with alveolar soft part sarcoma critical region 1 (ASPSCR1) at 17q25.
The study objective was to develop and validate a TFE3 break-apart fluorescence in situ hybridization (FISH) assay to confirm Xp11 translocation RCCs and ASPS.
The molecular signature of ASPS is a specific der(17)t(X;17)(p11.2;q25) translocation, which results in the fusion of TFE3 transcription factor gene at Xp11.2 with ASPL at 17q25.
Molecular cytogenetic analysis for TFE3 rearrangement in Xp11.2 renal cell carcinoma and alveolar soft part sarcoma: validation and clinical experience with 75 cases.
Alveolar soft part sarcoma (ASPS), a deadly soft tissue malignancy with a predilection for adolescents and young adults, associates consistently with t(X;17) translocations that generate the fusion gene ASPSCR1-TFE3.
The current report describes a unique case of vulvovaginal alveolar soft part sarcoma showing the classic morphologic features with documentation of TFE3 protein expression and the ASPL-TFE3 gene rearrangement.
Recently, a small subgroup of PEComas has been recognized to harbor rearrangements involving TFE3, a gene also involved in rearrangements in translocation-associated renal cell carcinomas and alveolar soft part sarcomas.
Integration of these data with expression profiles of ASPS tumour samples and inducible cell lines expressing ASPSCR1-TFE3 defined a subset of 332 genes as putative up-regulated direct targets of ASPSCR1-TFE3, including MET (a previously known target gene) and 64 genes as down-regulated targets of ASPSCR1-TFE3.