HER2 Amplification Associated with Urothelial Carcinoma, FISH, Tissue
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Human epidermal growth factor receptor 2 (HER2) plays a fundamental role in cell growth, survival, and migration. The assessment of HER2 gene status is crucial for the management of breast cancer. Studies have shown that HER2 is also expressed in a proportion of urothelial carcinoma of the urinary bladder (UCB), making it a potential target for UCB therapy.
HER2-positive gene status is associated with aggressive UCB and provides independent prognostic information. Assessment of HER2 status may be used to identify patients at high risk of disease progression.
To guide therapy for patients with primary or metastatic urothelial tumors, as patients with HER2 amplification may be candidates for therapies that target the human epidermal growth factor receptor 2 (HER2) protein (eg, trastuzumab [Herceptin], pertuzumab, lapatinib)
Confirming the presence of HER2 amplification in cases with 2+ (low level) or 3+ (high level) HER2 protein overexpression by immunohistochemistry
An interpretive report is provided. Results are interpreted utilizing the 2013 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines for breast tumors.
Specimens with equivocal results require reflex or repeat testing per ASCO/CAP guidelines.
The degree of HER2 amplification varies in tumors. Some exhibit high levels of amplification (HER2:CEP17 ratio >4.0), whereas others exhibit low-level amplification (HER2:CEP17 ratio of 2.2-4.0). It is not currently known if patients with different levels of amplification have the same prognosis and response to therapy.
Reports also interpret the HER2 copy number changes relative to chromosome 17 copy number (aneusomy) or potential structural changes that increase HER2 copy number.
Rare cases may not show HER2 amplification but still have human epidermal growth factor receptor 2 (HER2) protein overexpression demonstrated by immunohistochemistry. The clinical significance of HER2 protein overexpression in the absence of HER2 gene amplification is unclear. However, these patients may have a worse prognosis and be candidates for treatments that target the HER2 protein or its downstream pathways.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test is only for primary or metastatic urothelial tumors.
-For breast tumors, order FHER2 / HER2 Amplification Associated with Breast Cancer, FISH, Tissue.
-For gastroesophageal tumors, order FH2GE / HER2 Amplification Associated with Gastroesophageal Cancer, FISH, Tissue.
-For all other tumor types, order FH2MT / HER2 Amplification, Miscellaneous Tumor, FISH, Tissue.
The HER2 FISH test is not approved by the FDA for this indication and should be used as an adjunct to existing clinical and pathologic information.
Optimum fixation should be between 6 and 72 hours in 10% neutral buffered formalin. Other types of fixatives should not be used.
The prognostic information provided by the HER2 status of a patient's tumor should not be interpreted in isolation because other prognostic features (eg, lymph node status, tumor size) may be of equal or greater importance in determining the patient's prognosis.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretative report will be provided.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Bolenz C, Shariat SF, Karakiewicz PI, et al: Human epidermal growth factor receptor 2 expression status provides independent prognostic information in patients with urothelial carcinoma of the urinary bladder. BJU Int 2010 Oct;106(8):1216-1222
2. Lae M, Couturier J, Oudard S, et al: Assessing HER2 gene amplification as a potential target for therapy in invasive urothelial bladder cancer with a standardized methodology: results in 1005 patients. Ann Oncol 2010 Apr;21(4):815-819
3. Gandour-Edwards R, Lara PN Jr, Folkins AK, et al: Does HER2/neu expression provide prognostic information in patients with advanced urothelial carcinoma? Cancer 2002 Sep 1;95(5):1009-1015
4. Wolff AC, Hammond ME, Hicks DG, et al: Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: American Society for Clinical Oncology/College of American Pathologists clinical practice guideline update. J Clin Onc 2013 Nov 1;31(31):3997-4013