Desmoplastic Small Round Cell Tumor : t(11;22) translocation
Image Description
Desmoplastic small round cell tumor (DSRCT) is associated with a unique chromosomal translocation t(11;22) (p13; q12) that involves the EWSR1 gene (on 22q12) and WT1 gene (on 11p13). The EWS protein is a member of FET family of RNA-binding proteins. The protein product of WT1 is a zinc-finger type transcription factor that downregulates growth factors, including platelet-derived growth factor. The translocation most frequently involves exon 7 of EWSR1 and exon 8 of WT1 and results in the expression of an oncogenic chimeric EWSR1-WT1 protein that acts as a powerful mitogen and permits tumor growth.
The EWSR1-WT1 fusion (which is unique to DSRCT) can be detected by RT-PCR or FISH on frozen or formalin-fixed paraffin-embedded tissue. In rare cases of DSRCT, the EWSR1 gene partners with FLI1 or ERG creating fusion proteins that are more commonly seen in Ewing Sarcoma and related tumors.
The image shows multicolour FISH-based karyotype from a case of paratesticular DSRCT showing t(11;22)(p13;q12); no secondary chromosomal alterations were detected. Rearranged chromosomes are indicated by arrowheads. Image Source: Cliteur et al. Clinical Sarcoma Research 2012; 2:3. Used under Creative Commons Attribution License
The EWSR1-WT1 fusion (which is unique to DSRCT) can be detected by RT-PCR or FISH on frozen or formalin-fixed paraffin-embedded tissue. In rare cases of DSRCT, the EWSR1 gene partners with FLI1 or ERG creating fusion proteins that are more commonly seen in Ewing Sarcoma and related tumors.
The image shows multicolour FISH-based karyotype from a case of paratesticular DSRCT showing t(11;22)(p13;q12); no secondary chromosomal alterations were detected. Rearranged chromosomes are indicated by arrowheads. Image Source: Cliteur et al. Clinical Sarcoma Research 2012; 2:3. Used under Creative Commons Attribution License