FISH - MDM2 (12q15) Gene Amplification Test
Short Name: FISH MDM2
Also known as: MDM2 Gene Amplification FISH Test, MDM2 FISH Assay, 12q15 Amplification Test, MDM2 Fluorescence In Situ Hybridization, Liposarcoma FISH Panel MDM2
FISH - MDM2 (12q15) Gene Amplification Test test available at DNA Labs India for ₹10,500. Uses FISH (Fluorescence In Situ Hybridization) on Formalin-Fixed Paraffin-Embedded (FFPE) Tissue Block samples. Results in Sample accepted daily by 4:00 PM. Reports are available within 4 working days from the date of sample receipt.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Pasupathy Arumugam
Consultant Pathologist · Reg: 21521
Last reviewed: September 7, 2026
Overview
The primary purpose of the FISH - MDM2 (12q15) Gene Amplification Test is to detect amplification of the MDM2 gene for the classification of certain adipocytic tumours. It helps distinguish well-differentiated liposarcoma (WDL/ALT) and dedifferentiated liposarcoma (DDLS) from benign lipomas and other high-grade sarcomas that may appear morphologically similar. This test plays a crucial role in guiding treatment decisions and prognosis assessment for patients with soft tissue tumours.
- Test Code
- 585
- CPT Code
- 88377
- ICD Code
- D48.1
- Price
- ₹10,500
- Sample Type
- Formalin-Fixed Paraffin-Embedded (FFPE) Tissue Block
- Result Time
- Sample accepted daily by 4:00 PM. Reports are available within 4 working days from the date of sample receipt.
- Fasting Required
- No
- Method
- FISH (Fluorescence In Situ Hybridization)
Sample Collection
Ensure the Duly filled Chromosome & FISH analysis Requisition Form (Form 17) is completed. Provide complete clinical history and histopathological findings on the requisition form. The tissue specimen must have been collected via biopsy or surgical excision and processed into a formalin-fixed paraffin-embedded (FFPE) block.
Method: Surgical biopsy or excision specimen preserved in formalin and embedded in paraffin
Laboratory Analysis
The tissue specimen is typically collected via core needle biopsy, incisional biopsy, or surgical excision by the treating surgeon or pathologist. The specimen is fixed in 10% neutral buffered formalin and subsequently processed and embedded in paraffin wax.
Report Delivery
The FFPE tissue block is shipped to the laboratory at room temperature. The block is sectioned and the FISH procedure is performed using MDM2-specific fluorescent probes. Results are reviewed by a qualified pathologist or cytogeneticist.
Timeline: Sample accepted daily by 4:00 PM. Reports are available within 4 working days from the date of sample receipt.
Patient Instructions
About This Test
Who Should Get This Test
The primary purpose of the FISH - MDM2 (12q15) Gene Amplification Test is to detect amplification of the MDM2 gene for the classification of certain adipocytic tumours. It helps distinguish well-differentiated liposarcoma (WDL/ALT) and dedifferentiated liposarcoma (DDLS) from benign lipomas and other high-grade sarcomas that may appear morphologically similar. This test plays a crucial role in guiding treatment decisions and prognosis assessment for patients with soft tissue tumours.
How to Prepare
- Submit formalin-fixed paraffin-embedded (FFPE) tissue block containing at least 10% tumour tissue
- Ship the specimen at room temperature
- Duly filled Chromosome & FISH analysis Requisition Form (Form 17) is mandatory
- Include relevant clinical history and prior histopathology reports
- Label the specimen block clearly with patient name, ID, and date of collection
- Ensure the tissue block is sealed and protected during transport
Doctor's Notes
Reviewed by Dr Pasupathy Arumugam — MBBS, MD (Pathology) · Reg. No. 21521
"MDM2 gene amplification detected by FISH is a critical diagnostic marker for distinguishing well-differentiated and dedifferentiated liposarcoma from benign lipomas and other high-grade sarcomas. This test has become an essential part of the diagnostic workup for adipocytic tumors, as morphological evaluation alone can be challenging. I recommend this test for any adipocytic tumor where the differential diagnosis includes liposarcoma, particularly when histopathological findings are ambiguous."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- FFPE tissue block with less than 10% tumour tissue content
- Incomplete or missing Chromosome & FISH analysis Requisition Form (Form 17)
- Specimen showing extensive necrosis (>90%) with insufficient viable tumour cells
- Unlabelled or mislabelled specimen blocks
- Severely degraded or autolysed tissue samples
- Specimen collected in fixatives other than 10% neutral buffered formalin
Understanding Your Results
Positive - MDM2 Amplification Detected
Amplification of the MDM2 gene at the 12q15 locus is detected. This is consistent with well-differentiated liposarcoma (WDL)/atypical lipomatous tumour (ALT) or dedifferentiated liposarcoma (DDLS). Clinical correlation with histopathological and radiological findings is recommended.
Clinical action: Confirm diagnosis of liposarcoma subtype. Discuss treatment options with oncologist including surgical resection with adequate margins. Consider additional staging and follow-up imaging.
Negative - No MDM2 Amplification Detected
No amplification of the MDM2 gene is detected. This result does not support a diagnosis of well-differentiated or dedifferentiated liposarcoma. The tumour may represent a benign lipoma or another soft tissue tumour subtype. Rare liposarcoma cases with alternative molecular mechanisms may not show MDM2 amplification.
Clinical action: Consider alternative diagnoses based on morphological and immunohistochemical findings. Correlate with clinical presentation. If clinical suspicion remains high, discuss with pathologist regarding additional molecular or immunohistochemical testing.
Inconclusive / Uninterpretable
The FISH signals could not be adequately evaluated due to technical issues such as insufficient tumour tissue, poor signal quality, or tissue processing artefacts. The test may need to be repeated with an alternative tissue block or after re-processing.
Clinical action: Submit additional tissue if available. Ensure proper fixation and processing. Discuss with laboratory regarding repeat testing.
Consult your oncologist or treating physician if you have been diagnosed with a soft tissue tumour and need molecular confirmation for classification. If you have a lipomatous tumour in a deep or retroperitoneal location, or if histopathological findings are inconclusive regarding whether the tumour is benign or malignant, discuss with your doctor whether MDM2 FISH testing is appropriate. Additionally, consult your doctor after receiving your test results for proper interpretation, treatment planning, and follow-up recommendations.
Limitations
- ⚠This test detects MDM2 gene amplification only; it does not assess MDM2 protein expression levels
- ⚠A negative result does not completely exclude liposarcoma, as rare cases may show alternative molecular alterations
- ⚠FISH does not provide information about the overall chromosomal landscape; it targets only the MDM2 locus
- ⚠Subclonal amplification may be missed if only a small proportion of tumour cells harbour the alteration
- ⚠Results must always be interpreted in conjunction with clinical, radiological, and histopathological findings
Risks & Considerations
- ●This test is performed on an already collected tissue specimen; there are no additional physical risks to the patient from the FISH testing procedure itself
- ●In rare cases, the test may yield inconclusive results requiring repeat testing with an additional tissue sample
- ●False-negative results may occur in tumours with low-level or heterogeneous MDM2 amplification
Interfering Factors
- ●Inadequate tumour content in the submitted tissue block (must contain at least 10% tumour tissue)
- ●Excessive formalin fixation time may reduce FISH signal intensity
- ●Tissue necrosis or significant autolysis may affect probe hybridization
- ●Improperly processed or poorly preserved paraffin-embedded tissue
- ●Use of decalcifying agents on bone tissue specimens may degrade DNA
Compare With Similar Tests
| Test | FISH - MDM2 (12q15) Gene Amplification Test | Immunohistochemistry (IHC) for MDM2 | MDM2 by RT-PCR | CDK4 FISH |
|---|---|---|---|---|
| Comparison | FISH - MDM2 (12q15) Gene Amplification Test | IHC detects MDM2 protein expression while FISH detects gene amplification. FISH is considered more specific for liposarcoma diagnosis. IHC may show false positives due to non-amplification-related protein overexpression. | RT-PCR measures MDM2 mRNA expression levels. FISH provides direct visualization of gene copy number and is preferred for formalin-fixed paraffin-embedded tissue specimens. FISH is more widely validated for liposarcoma classification. | CDK4 is co-amplified with MDM2 in liposarcomas. Both markers are often used together in a FISH panel. CDK4 FISH alone may miss some cases, while MDM2 is considered a more robust single marker. |
Frequently Asked Questions
What is the FISH - MDM2 (12q15) Gene Amplification Test?
Why is the MDM2 FISH test recommended?
What sample is required for the MDM2 FISH test?
How is the FISH procedure performed?
What does a positive MDM2 FISH result mean?
What does a negative MDM2 FISH result mean?
What is the cost of the FISH - MDM2 test at DNA Labs India?
Is home sample collection available for this test?
How long does it take to get the results?
Is the MDM2 FISH test the same as an MDM2 immunohistochemistry (IHC) test?
Do I need a doctor's prescription for this test?
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