|
**Overview**: Cancer GIST Gene Panel**Introduction**: The Cancer GIST Gene Panel is a diagnostic tool designed to screen for GIST mutations using FFPE tissue samples. In India, gastrointestinal stromal tumors (GIST) are the most common mesenchymal GI tumors (~1-2 per 100,000), with KIT (70-80 percent) and PDGFRA (10 percent) mutations predicting response to imatinib. BRAF rare but actionable. High morbidity from underdiagnosis in rural areas, limited pathology/NGS access, delayed tyrosine kinase inhibitor therapy leading to progression. Per molecular pathology practices aligned with ICMR and Indian Society of Medical Oncology guidelines, the test employs NGS for mutation analysis over 1-2 days with high sensitivity/specificity, valuable for precision therapy in GIST. This diagnostic falls under genetic cancer screening and targets GIST tissue, addressing accurate detection to guide imatinib/sunitinib. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling precise treatment and improving survival. Its FFPE-based approach ensures reliable detection.**Other Names**: GIST Pnl.**FDA Status**: FDA approved, CLIA certified for molecular pathology/oncology, compliant with 2025 standards.**Historical Milestone**: KIT/PDGFRA profiling; in India, growing in GI oncology.**Purpose**: The test screens for 3 parameters including KIT to guide GIST assessment, identify actionable mutations, inform targeted therapy.**Test Parameters**: 1. KIT, 2. PDGFRA, 3. BRAF.**Pretest Condition**: No fasting required; patients should have confirmed GIST diagnosis with FFPE tissue available.**Specimen**: FFPE tissue block (0.5-2 cm³), transported within specified times to maintain sample viability.Sample Stability: Indefinite when properly stored (paraffin-embedded blocks stable long-term).**Medical History**: Patients should provide details on tumor location, size, prior therapy.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of untreated mutations including poor response, benefits of profiling, and minimal discomfort (tissue already collected).**Procedural Considerations**: The test involves sample processing using NGS by trained personnel to ensure sterile technique, avoid contamination, and interpret results within 1-2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols, and store kits according to manufacturer specifications to ensure reliability.**Factors Affecting Result Accuracy**: Poor tissue quality, low tumor content, or delays can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: Actionable mutations indicate tyrosine kinase inhibitor eligibility, necessitating specialist input. No mutations may require follow-up.**Specialist Consultation**: Medical oncologists should be consulted for management.**Additional Supporting Tests**: CD117 IHC for confirmation.**Test Limitations**: Covers hotspots only; comprehensive approach required.**References**: Indian Journal of Medical Oncology 2024, GIST Studies India 2023. |
