1P/19Q DEL Oligodendroglioma by fish (AKU) at Dr. Essa Lab

1P/19Q DEL Oligodendroglioma by fish (AKU) at Dr. Essa Lab

The 1P/19Q DEL Oligodendroglioma by fish (AKU) at Dr. Essa Lab is a highly specialized molecular cytogenetic test designed to detect the co-deletion of the short arm of chromosome 1 (1p) and the long arm of chromosome 19 (19q). This specific genetic alteration is the diagnostic hallmark of oligodendrogliomas, a distinct subtype of primary brain tumors. By utilizing Fluorescence In Situ Hybridization (FISH) technology, molecular pathologists can identify these chromosomal deletions with exceptional precision. This test is crucial for neuro-oncologists and neurosurgeons across Pakistan, particularly in Karachi, as it provides definitive diagnostic, prognostic, and predictive information that directly influences the clinical management of patients presenting with diffuse gliomas.

Fluorescence In Situ Hybridization (FISH) works by employing fluorescently labeled DNA probes that are complementary to specific target sequences on the 1p36 and 19q13 chromosomal regions. When these probes hybridize with the patient’s tumor DNA extracted from biopsy or surgical resection tissue, they emit distinct fluorescent signals under a specialized fluorescence microscope. Pathologists count these signals within the nuclei of tumor cells to determine if one copy of each region has been lost. The presence of the combined 1p/19q co-deletion confirms a diagnosis of oligodendroglioma, distinguishing it from other histologically similar brain tumors such as diffuse astrocytomas or glioblastomas. This differentiation is vital because oligodendrogliomas carry a significantly more favorable prognosis and demonstrate a superior response to specific chemotherapy regimens and radiation therapy.

Clinical Procedure: What to Expect

Patient Preparation

Because the 1P/19Q DEL Oligodendroglioma by fish (AKU) test is performed on tissue samples that have already been surgically removed during a biopsy or craniotomy, there is no direct physical preparation required from the patient at the time of the laboratory analysis. However, patients and their families should keep the following points in mind regarding the submission of sample materials:

• Tissue Block Submission: The primary requirement is the submission of the Formalin-Fixed Paraffin-Embedded (FFPE) tissue block, along with the corresponding histopathology slides and report from the initial surgery.
• Surgical Documentation: Patients must provide all relevant clinical history, neuroimaging reports (such as MRI or CT scans of the brain), and previous pathology reports to Dr. Essa Lab.
• Coordination with the Hospital: If the surgery was performed at an external hospital, patients may need to coordinate with that institution’s pathology department to release the paraffin block and slides for testing.
• No Fasting Required: Since no new blood draw or invasive procedure is performed on the patient for this specific molecular test, fasting or medication adjustments are not necessary.

During the Procedure

The laboratory phase of the 1P/19Q DEL Oligodendroglioma by fish (AKU) test involves a meticulous, multi-step molecular protocol conducted by specialized laboratory technologists at Dr. Essa Lab:

• Sample Selection: A consultant pathologist reviews the submitted histopathology slides to identify the areas of the tissue block with the highest density of viable tumor cells, avoiding areas of necrosis or extensive hemorrhage.
• Sectioning: Ultra-thin sections (typically 4 to 5 micrometers thick) are cut from the selected FFPE tissue block and mounted on positively charged glass slides.
• Deparaffinization and Pretreatment: The tissue sections undergo deparaffinization, rehydration, and enzymatic pretreatment to make the target nuclear DNA accessible to the molecular probes.
• Probe Hybridization: Dual-color probe sets specific for the 1p36/1q25 and 19q13/19p13 regions are applied to the slides. The slides are then heated to denature the DNA and incubated overnight to allow the probes to hybridize with their target chromosomal sequences.
• Washing and Counterstaining: Post-hybridization washes are performed to remove unbound probes. The cell nuclei are counterstained with DAPI (4′,6-diamidino-2-phenylindole), which fluoresces blue.
• Microscopic Analysis: A molecular pathologist examines the slides under a high-resolution fluorescence microscope equipped with appropriate filters. The pathologist counts the green and orange signals in at least 100 non-overlapping tumor nuclei to calculate the deletion ratio.

When is a 1P/19Q DEL Oligodendroglioma by fish (AKU) Performed?

Differential Diagnosis of Diffuse Gliomas

Physicians request this test when a patient presents with a diffuse glial tumor that shows overlapping histological features under the microscope. Because astrocytomas and oligodendrogliomas can look remarkably similar on standard hematoxylin and eosin (H&E) stained slides, detecting the 1p/19q co-deletion provides an objective, molecular-level confirmation that the tumor is indeed an oligodendroglioma, which is essential for accurate World Health Organization (WHO) classification.

Prognostic Evaluation of Brain Tumors

The presence of the 1p/19q co-deletion is a powerful positive prognostic indicator. Patients whose tumors harbor this genetic signature generally experience significantly longer progression-free survival and overall survival compared to those with non-co-deleted gliomas. Oncologists order this test to stratify patient risk and counsel families realistically about the clinical course of the disease.

Predicting Chemotherapy and Radiotherapy Sensitivity

Clinical trials have definitively demonstrated that oligodendrogliomas with 1p/19q co-deletions are highly sensitive to alkylating chemotherapy agents (such as temozolomide or the PCV regimen consisting of procarbazine, CCNU, and vincristine) as well as radiation therapy. This test is performed to help neuro-oncologists design an optimal, personalized post-surgical treatment plan.

Clarification of Mixed Glioma Histology

In cases where the tumor exhibits mixed features of both astrocytoma and oligodendroglioma (previously referred to as oligoastrocytomas), histological classification can be highly subjective. The 1p/19q FISH test resolves this ambiguity; tumors with the co-deletion are classified as oligodendrogliomas, while those without it (often harboring TP53 or ATRX mutations) are classified as astrocytomas.

Assessment of Recurrent Glial Lesions

When a previously treated brain tumor recurs, clinicians may request a molecular re-evaluation. Confirming the retention of the 1p/19q co-deletion status in recurrent tissue helps determine whether the tumor remains eligible for targeted chemotherapy protocols or if secondary molecular alterations have occurred over time.

What Does a 1P/19Q DEL Oligodendroglioma by fish (AKU) Detect?

The 1P/19Q DEL Oligodendroglioma by fish (AKU) test is capable of detecting a wide range of cytogenetic patterns and technical parameters within the evaluated brain tumor tissue, including:

• Complete co-deletion of chromosome arms 1p and 19q
• Isolated deletion of the 1p36 locus
• Isolated deletion of the 19q13 locus
• Intact (normal) diploid status of both 1p and 19q loci
• Polysomy (extra copies) of chromosome 1
• Polysomy (extra copies) of chromosome 19
• Relative deletion ratios between target and reference probes
• Heterozygous deletion patterns in tumor cell subpopulations
• Homozygous deletion of specific chromosomal regions
• Tumor heterogeneity and clonal evolution within the sample
• Percentage of tumor cells harboring the co-deletion
• Presence of structural chromosomal rearrangements
• Atypical hybridization signal patterns
• Adequacy of tumor cell cellularity in the submitted tissue section
• Presence of tissue artifacts affecting hybridization
• Background autofluorescence levels
• Quality of nuclear morphology under fluorescence
• Integrity of the control probe signals (1q25 and 19p13)
• Evaluation of non-neoplastic stromal cells as internal controls
• Technical suitability of the paraffin block for molecular testing

Turnaround Time and Report Access at Dr. Essa Lab

At Dr. Essa Lab, we understand that waiting for brain tumor molecular results can be an anxious time for patients and their families. Because Fluorescence In Situ Hybridization (FISH) is a complex, multi-day laboratory procedure requiring precise tissue processing, overnight hybridization, and expert pathological review, the turnaround time is typically 7 to 10 working days. Dr. Essa Lab offers convenient digital report access, allowing patients and referring physicians to view and download the verified molecular pathology reports directly from our secure online portal or mobile application as soon as they are finalized by our consultant pathologists.

1P/19Q DEL Oligodendroglioma by fish (AKU) Findings Overview

Structure / Parameter Evaluated	Normal Findings	Possible Abnormal Findings
1p36 Locus Status	Two signals per nucleus (normal diploid)	One signal per nucleus (deletion of 1p)
19q13 Locus Status	Two signals per nucleus (normal diploid)	One signal per nucleus (deletion of 19q)
1p/19q Co-deletion Status	No co-deletion detected	Concurrent deletion of both 1p and 19q loci
1q25 Reference Locus	Two signals per nucleus	Loss or gain of reference signals (unbalanced translocation)
19p13 Reference Locus	Two signals per nucleus	Loss or gain of reference signals (unbalanced translocation)
Deletion Ratio (Target/Reference)	Ratio close to 1.0	Ratio significantly less than 0.5 (indicating deletion)
Tumor Cell Cellularity	Adequate tumor cells for evaluation (>70%)	Inadequate cellularity or extensive necrosis
Chromosomal Ploidy	Diploid signal pattern	Polysomy, triploidy, or complex aneuploidy

Note: Diagnostic findings should always be interpreted by a qualified healthcare professional together with the patient’s symptoms, medical history, physical examination, laboratory investigations, previous imaging studies, and other relevant clinical information. Additional investigations or specialist consultation may be recommended depending on the findings.

Why Choose Dr. Essa Lab for 1P/19Q DEL Oligodendroglioma by fish (AKU)?

• Experienced Healthcare Professionals: Our molecular pathology department is led by highly trained pathologists specializing in cytogenetics and neuro-oncology diagnostics.
• Patient-Focused Care: We prioritize patient comfort, clear communication, and compassionate support throughout the diagnostic journey.
• Quality Diagnostic Services: Dr. Essa Lab adheres to strict international quality control standards to ensure the highest accuracy in molecular testing.
• Professional Reporting: Our reports provide clear, comprehensive, and clinically actionable data that help oncologists make informed treatment decisions.
• Modern Diagnostic Approach: We utilize advanced fluorescence microscopy and high-quality locus-specific probes for precise chromosomal analysis.
• Comfortable Environment: Our diagnostic centers across Pakistan offer a welcoming and professional atmosphere for sample submission and consultation.
• Convenient Location: With an extensive network of branches in Karachi and other major cities, accessing our diagnostic services is highly convenient.
• Commitment to Accurate Diagnosis: We are dedicated to providing timely, reliable, and evidence-based diagnostic insights to support effective patient care.