(Tp53/17p13.1) by FISH (Research purpose only) at Chughtai Lab

The (Tp53/17p13.1) by FISH (Research purpose only) at Chughtai Lab is a highly specialized molecular cytogenetic investigation designed to detect deletions, microdeletions, or structural rearrangements involving the TP53 gene locus on the short arm of chromosome 17 (specifically at the 17p13.1 cytogenetic band). This advanced diagnostic tool utilizes Fluorescence In Situ Hybridization (FISH) technology, a powerful molecular biology technique that allows pathologists and researchers to visualize specific genomic sequences directly within interphase nuclei or metaphase chromosomes. The TP53 gene is widely recognized as the guardian of the genome, encoding the p53 tumor suppressor protein which plays a critical role in regulating the cell cycle, initiating DNA repair mechanisms, and triggering programmed cell death (apoptosis) in response to cellular stress or DNA damage. When the TP53 gene is deleted or mutated, cells lose their primary defense mechanism against genomic instability, leading to uncontrolled cellular proliferation and resistance to conventional therapeutic agents. This specific assay is designated for research purposes only, meaning it serves as an invaluable tool for translational oncology, clinical trials, academic research, and investigational studies aimed at understanding the genomic landscape of hematological malignancies and solid tumors across Pakistan.

By utilizing locus-specific fluorophore-labeled DNA probes, the (Tp53/17p13.1) by FISH (Research purpose only) test provides exceptional sensitivity and specificity compared to traditional karyotyping. Traditional cytogenetics often fails to detect microdeletions due to the limited resolution of G-banded chromosomes. In contrast, FISH bypasses the requirement for actively dividing cells, allowing for the direct analysis of interphase nuclei obtained from peripheral blood, bone marrow aspirates, or paraffin-embedded tissue sections. The diagnostic value of identifying a 17p13.1 deletion is profound, particularly in hematological conditions such as Chronic Lymphocytic Leukemia (CLL), Multiple Myeloma, and Acute Myeloid Leukemia (AML). In these clinical contexts, the loss of the TP53 locus is strongly associated with an aggressive disease course, poor prognosis, and resistance to standard alkylating agents and purine analogues. Consequently, this molecular assay is crucial for stratifying risk profiles, evaluating clonal evolution, and exploring novel targeted therapeutic pathways in research settings at Chughtai Lab.

Clinical Procedure: What to Expect

Patient Preparation

Appropriate patient preparation is essential to ensure the integrity of the biological specimen and the accuracy of the molecular cytogenetic analysis. For the (Tp53/17p13.1) by FISH (Research purpose only) test, the preparation guidelines depend primarily on the specimen type requested by the referring physician or research protocol. If the test is performed on a peripheral blood sample, fasting is generally not required, and patients can continue their normal diet and hydration. However, patients must inform their healthcare provider of all current medications, especially anticoagulants, chemotherapy agents, or immunosuppressants, as these can influence cellularity and sample quality. If a bone marrow aspirate is required, more comprehensive preparation is necessary, including a detailed clinical consultation, evaluation of coagulation profiles, and potential temporary cessation of blood-thinning medications under strict medical supervision. Patients should wear comfortable clothing and arrive at the Chughtai Lab collection center well-hydrated to facilitate an optimal venipuncture or bone marrow procedure.

During the Procedure

The procedure begins with the collection of the appropriate biological specimen under strict aseptic conditions. For a peripheral blood sample, a skilled phlebotomist at Chughtai Lab performs a standard venipuncture, typically drawing blood from a vein in the arm into a specialized sodium heparin tube, which preserves cell viability for cytogenetic analysis. If a bone marrow aspirate is indicated, a qualified hematologist performs the procedure under local anesthesia, extracting a small volume of bone marrow fluid from the posterior iliac crest. Once the sample is received at the specialized molecular diagnostics department of Chughtai Lab, it undergoes a series of meticulous laboratory steps. The cells are harvested, fixed onto glass slides, and subjected to enzymatic digestion to make the target DNA accessible. The fluorophore-labeled DNA probes specific to the TP53 locus (17p13.1) and a control probe (typically targeting the centromere of chromosome 17, CEP 17) are applied to the slide. The target DNA and the probes are co-denatured using heat and then allowed to hybridize overnight in a controlled humidified chamber. Post-hybridization washes are performed to remove unbound probes, and the cell nuclei are counterstained with DAPI. Finally, an experienced pathologist or cytogeneticist analyzes the slides using a high-resolution fluorescence microscope equipped with specialized narrow-bandpass filters, counting a minimum of 100 to 200 interphase nuclei to determine the exact signal patterns and calculate the percentage of cells harboring the deletion.

When is a (Tp53/17p13.1) by FISH (Research purpose only) Performed?

Evaluation of Chronic Lymphocytic Leukemia (CLL)

In the context of Chronic Lymphocytic Leukemia, evaluating the status of the TP53 gene is one of the most critical prognostic steps. Physicians and clinical researchers request this test to identify the presence of the 17p13.1 deletion, which occurs in approximately 5 to 10 percent of treatment-naive CLL patients and up to 40 percent of patients with refractory or relapsed disease. Detecting this deletion is vital because CLL patients with a TP53 deletion do not respond favorably to standard chemoimmunotherapy regimens, such as fludarabine, cyclophosphamide, and rituximab (FCR). Identifying this genetic alteration helps researchers and clinicians explore alternative therapeutic strategies, including B-cell receptor inhibitors or BCL-2 inhibitors, which bypass the p53 pathway.

Assessment of Multiple Myeloma

Multiple Myeloma is characterized by significant genetic heterogeneity, and the deletion of the short arm of chromosome 17 (del(17p)) is recognized as one of the most important high-risk cytogenetic abnormalities. The (Tp53/17p13.1) by FISH (Research purpose only) test is performed to detect this deletion in plasma cells, which is associated with shorter progression-free survival and overall survival. Understanding the TP53 status in myeloma patients is essential for risk-adapted stratification in clinical research, helping to evaluate the efficacy of novel proteasome inhibitors, immunomodulatory drugs, and autologous stem cell transplantation in patients harboring this high-risk genetic marker.

Investigating Myelodysplastic Syndromes (MDS)

Myelodysplastic Syndromes represent a group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis and a high risk of transformation to Acute Myeloid Leukemia. The presence of TP53 mutations or deletions is associated with a highly complex karyotype, rapid disease progression, and poor response to hypomethylating agents. Performing the TP53 FISH test allows researchers to identify patients with high-risk disease, monitor clonal evolution, and study the molecular mechanisms driving leukemic transformation within the Pakistani patient population.

Translational Oncology and Clinical Research

Because this test is designated for research purposes, it is frequently utilized in clinical trials and translational research studies conducted across academic medical centers in Pakistan. Researchers use the (Tp53/17p13.1) by FISH assay to correlate genomic deletions with clinical outcomes, evaluate the pharmacodynamics of experimental targeted therapies, and map the prevalence of TP53 deletions across different demographic groups. This contributes significantly to the global scientific database and helps in designing future diagnostic and therapeutic protocols tailored to the genetic profile of local patients.

Prognostic Stratification in Solid Tumors

Beyond hematological malignancies, the TP53 gene is frequently altered in a wide variety of solid tumors, including breast, lung, colorectal, and ovarian cancers. In research settings, the FISH assay can be performed on formalin-fixed paraffin-embedded (FFPE) tissue sections to assess the copy number status of the TP53 gene. This assists researchers in understanding tumor biology, evaluating the correlation between TP53 deletion and tumor grade, and investigating the role of p53 loss in mediating resistance to radiotherapy and conventional chemotherapy agents.

What Does a (Tp53/17p13.1) by FISH (Research purpose only) Detect?

The (Tp53/17p13.1) by FISH (Research purpose only) test is designed to detect a wide spectrum of numerical and structural abnormalities involving chromosome 17 and the TP53 gene locus. Specifically, the assay detects:

• TP53 Gene Deletion: The physical loss of one or both copies of the TP53 gene at the 17p13.1 locus.
• Hemizygous Deletion: The loss of a single allele of the TP53 gene, resulting in a single fluorescent signal instead of the normal two.
• Homozygous Deletion: The rare and severe loss of both alleles of the TP53 gene, characterized by the complete absence of the TP53 signal in the presence of control signals.
• Monosomy 17: The loss of an entire chromosome 17, indicated by a single TP53 signal and a single CEP 17 control signal.
• Polysomy 17: The presence of extra copies of chromosome 17, characterized by multiple CEP 17 and TP53 signals.
• Atypical Signal Patterns: Complex structural rearrangements, translocations, or insertions involving the 17p13.1 region.
• Clonal Mosaicism: The coexistence of genetically normal cell populations alongside clones harboring the TP53 deletion.
• Percentage of Deleted Cells: The precise quantification of the abnormal clone size within the analyzed cell population.
• Hybridization Efficiency: The quality and specificity of probe binding to the target genomic sequences.
• Nuclear Morphology: Structural abnormalities in the nuclei of the evaluated cells.
• Signal Amplification: An abnormal increase in the copy number of the TP53 gene relative to the centromere.
• Clonal Evolution: Changes in the proportion of deleted cells over time or in response to experimental therapies.
• Background Fluorescence: Assessment of non-specific binding to ensure diagnostic clarity.
• Interphase Nuclei Adequacy: Evaluation of the suitability of the cell nuclei for accurate counting.
• Control Probe Integrity: Verification that the CEP 17 probe has hybridized correctly to confirm chromosome count.
• DAPI Counterstain Quality: Ensuring optimal nuclear visualization under fluorescence microscopy.
• Cellular Heterogeneity: Variations in genetic makeup across different cell lineages in the sample.
• Microdeletions: Submicroscopic deletions at the 17p13.1 locus that cannot be resolved by standard karyotyping.
• Structural Rearrangements: Breaks or fusions near the TP53 locus.
• Sample Cellularity: The overall concentration and health of the cells provided in the specimen.

Turnaround Time and Report Access at Chughtai Lab

Chughtai Lab is committed to providing accurate and timely diagnostic and research reports. Due to the highly complex and specialized nature of molecular cytogenetics, the turnaround time for the (Tp53/17p13.1) by FISH (Research purpose only) test typically ranges from several days to a week. This duration allows for meticulous sample processing, overnight hybridization, detailed microscopic analysis of multiple cell nuclei by specialized cytogeneticists, and a rigorous multi-step quality control review. Once the report is finalized, patients and researchers can access the results conveniently through the Chughtai Lab online portal, the dedicated Chughtai Lab mobile application, or via SMS alerts containing a direct download link. Physical copies of the report can also be collected from any of the numerous Chughtai Lab collection centers located across Pakistan, including major hubs in Lahore, Karachi, Islamabad, and Rawalpindi.

(Tp53/17p13.1) by FISH (Research purpose only) Findings Overview

Structure / Parameter Evaluated	Normal Findings	Possible Abnormal Findings
TP53 Locus (17p13.1)	Two distinct fluorescent signals per nucleus (diploid)	One signal (hemizygous deletion) or zero signals (homozygous deletion)
Chromosome 17 Centromere (CEP 17)	Two distinct control signals per nucleus	One signal (monosomy 17) or three or more signals (polysomy 17)
TP53 to CEP 17 Ratio	Ratio of approximately 1.0	Ratio significantly less than 1.0 (indicating selective deletion of the TP53 gene)
Percentage of Deleted Cells	Below the laboratory’s established normal cutoff (typically < 5-10%)	Elevated percentage of cells (e.g., 20%, 50%, or 90%) harboring the deletion
Signal Pattern per Nucleus	Standard 2O2G pattern (2 Orange TP53 signals, 2 Green CEP 17 signals)	Abnormal patterns such as 1O2G, 0O2G, 1O1G, or complex multi-signal patterns
Clonal Heterogeneity	Homogeneous population of normal diploid cells	Presence of multiple distinct clones with varying genetic abnormalities
Hybridization Quality	Bright, sharp, and distinct fluorescent signals with minimal background noise	Weak signals, high background autofluorescence, or failed hybridization requiring re-testing

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 Chughtai Lab for (Tp53/17p13.1) by FISH (Research purpose only)?

• Experienced Healthcare Professionals: Chughtai Lab boasts a team of highly qualified pathologists, molecular biologists, and cytogeneticists with extensive experience in genetic testing.
• Patient-Focused Care: Every step of the testing process is designed with the patient’s comfort, convenience, and peace of mind in mind.
• Quality Diagnostic Services: Chughtai Lab adheres to strict national and international quality standards, ensuring highly reliable and reproducible research results.
• Professional Reporting: Reports are detailed, comprehensive, and structured to provide clear, actionable insights for clinicians and researchers.
• Modern Diagnostic Approach: Utilizing state-of-the-art fluorescence microscopes, high-quality probes, and advanced molecular techniques.
• Comfortable Environment: All collection centers across Pakistan are designed to provide a clean, safe, and welcoming environment for patients.
• Convenient Location: With a vast network of labs and collection points nationwide, accessing specialized testing is simple and hassle-free.
• Commitment to Accurate Diagnosis: Chughtai Lab’s rigorous internal and external quality control programs guarantee the highest level of precision in molecular testing.