TOP IIA FISH
Histopathology Overview / Directory
Purpose of the test
Type II topoisomerases are enzymes that assist in the DNA replication and recombination by allowing topographical changes to the double helix and are also necessary for correct chromosome structure and segregation. The gene is located on chromosome 17q21-22 and its amplification and deletion is associated with the Her2 gene due to their close proximity in the genome.
As type II topoisomerases are the target for certain chemotherapeutic agents such as the anthracyclines, the copy number of the gene has been shown to have a bearing on the sensitivity of the tumour to these drugs. As such, demonstration of TOP2A has been shown to be a predictive marker in a variety of malignant tumours e.g. breast, gastric and colonic.
The copy number of the topoisomerase II gene can be assessed using fluorescent in situ hybridisation (FISH).
Sample Requirements
Paraffin processed blocks or sections of tumour.
Tissue that has been decalcified in acid is not suitable.
Turnaround Time
1 – 2 Weeks
Price
Price available on application - please contact adrianturner1@nhs.net. Discounts could be available for significant workloads.
Contacts
Jane Moorhead
T 020 3299 3091
Dr J Salisbury, Consultant Histopathologist and Departmental Head of Service
T 020 3299 3093
References
Coon JS, et al. Clin Canc Res 2002: 8; 1061-7.
Amplification and overexpression of topoisomerase II a predict response to anthracycline- based therapy in locally advanced breast cancer.
Jarvinen TA et al Am J Path 2000: 156; 839-47.
Amplification and deletion of topoisomerase II associate with ErbB-2 amplification and affect sensitivity to topoisomerase II inhibitor doxorubicin in breast cancer.
Wagner AD et al Cochrane Database Syst Rev. 2005: 18; CD004064
Chemotherapy for advanced gastric cancer.
