What is HER2 FISH test?
What is HER2 FISH test?
The FISH (fluorescence in situ hybridization) test checks the DNA of your cancer cells for extra copies of the HER2/neu gene. This gene makes proteins called HER2 (human epidermal growth factor receptor 2) that attach to the surface of all breast cells.
What is Gastric HER2?
The definition of fluorescence in situ hybridization or silver in situ hybridization positivity in gastric or gastro–esophageal junction cancer is a HER2:chromosome 17 ratio of ≥2.0.
What cancers are HER2 positive?
Bladder carcinomas, gallbladder, extrahepatic cholangiocarcinomas, cervical, uterine, and testicular cancers showed HER2 positivity rates of 12.4, 9.8, 6.3, 3.9, 3.0, and 2.4 %, respectively. HER2 overexpression and/or amplification is frequently found across tumor types.
How is HER2 amplification tested?
Currently, two methods of determining HER2 status are used routinely in clinical practice: immunohistochemistry (IHC), which assesses expression of the HER2 protein on the cell surface, and fluorescent in situ hybridisation (FISH), which detects amplification of the HER2 gene (Pauletti et al, 2000; Bartlett et al, 2001 …
Why is FISH test done?
Fluorescence in situ hybridization (FISH) is a test that “maps” the genetic material in human cells, including specific genes or portions of genes. Because a FISH test can detect genetic abnormalities associated with cancer, it’s useful for diagnosing some types of the disease.
How accurate is FISH test?
Accuracy and limitations. Prenatal interphase FISH testing is highly accurate, with reported false-positive and -negative rates usually less than 1%. The main problem, however, is that not all specimens are informative. Uninformative rates will vary among laboratories, but rates of 3% to 10% are considered typical.
What percentage of gastric patients are HER2-positive?
These results have been confirmed in a large number of patients in the ToGA study, in which HER2 positivity was found in 32% and 18% in GEJ and gastric cancers, respectively [31].
How do you read HER2 FISH results?
Answer
- Positive HER2 amplification: FISH ratio is greater than 2.2 or HER2 gene copy is greater than 6.0.
- Equivocal HER2 amplification: FISH ratio of 1.8-2.2 or HER2 gene copy of 4.0-6.0.
- Negative HER2 amplification: FISH ratio is less than 1.8 or HER2 gene copy of less than 4.0.
What is amplification of HER2?
Amplification of the HER2 gene is the primary mechanism of HER2 overexpression in tumors1. HER2 amplification occurs before HER2 protein overexpression and monitoring of the tumor HER2 gene amplification status has therefore become routine in breast cancer2,3,4 surveillance.
How is HER2 testing in gastric cancer different from breast cancer?
HER2 testing in gastric cancer differs from testing in breast cancer due to inherent differences in tumor biology; gastric cancer more frequently shows HER2 heterogeneity (focal staining) and incomplete membrane staining.
Is HER2 an independent prognostic biomarker in early oesophago-gastric adenocarcinoma?
HER2 status seems not to be an independent prognostic biomarker in early oesophago-gastric adenocarcinoma. HER2 as a Predictive Biomarker in Gastric Cancer Clinically, HER2 has been established as a predictive biomarker for HER2-targeted therapies. In gastric cancer, it is a predictive biomarker for treatment with trastuzumab.
What is the immunohistochemistry score for HER2 HER2?
Immunohistochemistry for HER2 is scored on a 4 tiered scale that ranges from 0 to 3+ Strong lateral or complete basolateral membrane staining is adequate for positivity in gastric and GEJ adenocarcinomas, unlike in breast cancers, where circumferential membrane reactivity is required for positivity
How to measure HER2 protein levels with response in trastuzumab for toga?
Given the predictive value of HER2 protein levels with response in the trastuzumab for GAstric cancer study (ToGA), immunohistochemistry should be the initial testing methodology and fluorescence in situ hybridization or silver in situ hybridization should be used to retest immunohistochemistry 2+ samples.
