INTERPHASE FLUORESCENCE IN SITU HYBRIDIZATION TEST FOR BREAST CANCER TISSUES, GASTRIC/GASTRO-OESOPHAGEAL JUNCTION CARCINOMAS (GEJ) USING HER2 (ERBB2) DNA PROBE

​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.

​Fluorescence In Situ Hybridization using direct-labelled LSI HER2 (ERBB2) and CEP 17 DNA probes are hybridized to target loci and analysed under fluorescence microscopy.

​Findings are reported in accordance to the International System for Human Cytogenomic Nomenclature (ISCN, 2024).

​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 ~ 9 days

​Monday – Saturday (office hours)