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TP53-rearranged osteosarcoma

Thursday 22 March 2018

Osteogenic sarcoma (OS) is the most common malignant bone tumor in children and adolescents. Despite advances in molecular genetic characterization of pediatric and adult tumors, the diagnosis of OS still depends almost entirely on light microscopy.

The lack of consistent genetic changes in OS has greatly hindered the development of any diagnostic molecular test.

Whole-genome sequencing has shown that 50% of cases of OS have a translocation involving the TP53 gene with breakpoints confined to the first intron.

A rearranged TP53 signal is found in 54% of OS and in none of the other sarcomas or benign bone lesions in the differential diagnosis, giving the FISH test 100% specificity for a diagnosis of OS.

p53 immunostaining was generally not predictive of the results obtained by FISH and could not substitute for this test.

This FISH probe offers a simple and specific genetic test to aid in the diagnosis of OS, despite the genetic complexity of this tumor.

Paywall references

- Fluorescent In Situ Hybridization for TP53 in the Diagnosis of Pediatric Osteogenic Sarcoma. Marrano P, Shago M, Somers GR, Thorner PS. Am J Surg Pathol. 2018 Mar 14. doi : 10.1097/PAS.0000000000001054 PMID: 29543677