FISH test using HER2 (ERBB2) DNA-probe is used in the detection of amplification of the HER2 (ERBB2) gene that plays a key role in the regulation of cell growth. This gene is amplified in some patients with human breast and gastric cancer. These patients respond well to trastuzumab (Herceptin®) treatment.
Newly-cut fresh breast cancer sections is ideal.
The FISH test is optimal with fresh tissue samples. Tissue sections should preferably be between 4 - 6mm in thickness on coated/positively-charged slides. The optimal fixation time in formalin should be between 6 - 72 hours. An accompanying Hematoxylin and Eosin (H&E) stained slide with the invasive tumour region marked out by a pathologist should be submitted together with at least 3 unstained sections.
Findings are reported in accordance to the International System for Human Cytogenomic Nomenclature (ISCN, 2016).
ASCO/CAP guidelines - Reference ranges for ERBB2 amplification: 1. Positive - Ratio greater or equal to 2.0. 2. Positive - Ratio less than 2.0 with average ERBB2 copy numbers greater or equal to 6.0 signals/cell. 3. Equivocal - Ratio less than 2.0 with average ERBB2 copy numbers greater or equal to 4.0 and less than 6.0 signals/cell. 4. Negative - Ratio less than 2.0 with average ERBB2 copy numbers less than 4.0 signals/cell. For gastric/GEJ carcinomas, results are positive if the ratio is ≥2.0
3 ~ 10 days
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