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Bladder cancer marker test
Detection are the main problems of bladder cancer. Established techniques for detecting and monitoring bladder cancer include cystoscopy, cytology of urine, and urinalysis, which includes both dipstick and microscopic examination to detect microscopic hematuria. The initial diag nosis of bladder cancer can be problematic because the most common presenting symptoms on initial examination are painless hematuria and irritative voiding, which are nonspecific. For example, hema turia is the most prevalent presenting symptom, and it occurs in only 4-10 % of bladder cancers. Al though urinalysis and microscopic examination are accurate for detecting microhematuria, both lack sensitivity and specificity for bladder cancer.
Exfoliated malignant cells, which are present in urine sediment have large and eccentric nuclei with a higher ratio of nucleus to cytoplasm and irregular coarse chromatin. Although urine cytology has a specificity of more than 90 % for diagnosis, it is not cost effective to perform this procedure for every patient with hematuria.
2. Rapid turnaround time for results is rare.
- The results are always subjective because pa thologists differ as to the exact definitions of normal and abnormal cellular morphology.
- Rapid turnaround time for results is rare.
- Poor sensitivity (20-40 %) for the most com mon low-grade lesions, regardless of the man ner of collection. (Poor sensitivity exists be cause cells in the urine sample for cytological examination appear normal despite the exist ence of a tumor)
- The most common, well-differentiated tumors (low-grade) are more cohesive, which make these cells less likely to shed into the urine.
- False-positive cytology results can occur in as many as 12 % of patients because of inflamma tion, urothelial atypia, and change caused by chemo-or radiation therapy.
- Urine cytology results are false negative in 20 % of patients with high-grade tumors.
Cystoscopy is visual examination of the urinary tract with a cystoscope designed specifically for bladder examination. This method provides the most valuable information for detecting and monitoring bladder cancer, with sensitivity at approximately 70
It allows the characterization of any tumors present as to number: multifocality, size and appcar ance. Cystoscopy gives most important prognostic information, such as tumor stage and grade. How ever, cystoscopy is also an invasive and costly pro cedure. It is also subject to human interpretation. For patients having abnormalities require cysto. scopic follow-up at least every 3 months or more depending on the stage and grade of any tumor detected.
BIOMARKERS for bladder cancer
BIOMARKERS may improve the screening and diagnosis of bladder cancer and determine its malig nant potential and prognosis. Following are ideal ways of testing biomarkers
- Specimens for tests using biomarkers should be easily obtained using non-invasive methods.
- Procedure should be cost effective and easy to use.
- Procedure should provide results rapidly for fast interpretation.
- The result should be accurate, precise and with high sensitivity and specificity.
Target group of patients
Target groups of patients for whom the bladder biomarker testing is required include the following criteria:
- Patients older than 65 years.
- Having history of smoking or another types of exposure to carcinogenic substances,
- Symptoms of bladder cancer: Hematuria or ir-ritable urinary symptoms such as urgency and frequency.
- Patients being monitored after bladder cancer diagnosis or treatment.
Currently, a variety of markers have been de veloped, and the following have been approved by the Food and Drug Administration (USA) to monitor patients with bladder cancer:
- Bladder tumor antigen (BTA)
- Fibrin / fibrinogen degradation product (FDP)
- Nuclear Matrix Protein (NMP22)
Bladder tumor antigen (BTA)
The BTA test detects the presence of basement mem brane complexes in the urine. Patient’s urine samples are mixed with latex particles coated with human IgG and agents for blocking nonspecific cross-re actions. If basement membrane complexes are articles and ag a color change present, they combine with latex particles glutinate. This reaction produces a color ch This differentiates positive from negative results a test strip. The higher the stage of tumor, the his the sensitivity of the test. The loss of these ba proteins into urine correlates with tumor sta grade.
BTA-stat assay detect a human complement factor H-related protein (hcFHrp) produced by several human bladder cancer cells. The qualitative, single. step immuno-chromatographic BTA stat test is a point-of-care dipstick test that can be performed in the physicians office and provides results within 5 minutes. Sensitivity of the BTA stat test for low grade lesions is higher than that of cytology but for high-grade lesions it is lower than that of cytology.
Fibrin/ fibrinogen degradation products (FDP)
The qualitative FDP test is based on the recognition that increased FDP levels in the urine are associ ated with the presence of malignant bladder tumors. This flow immunoassay uses monoclonal antibod ies to detect FDP and is a rapid point-of care dip stick test with an overall sensitivity of 82 % for all stages of bladder cancers. (Which is higher than that of cytology). Sensitivity for grading the tumors was 63.2 % for grade-I, 82 % for grade-2 and 95 % for grade-3 disease. The specificity is 80 % for patients being monitored for bladder cancer who have a nega tive cystoscopic examination at the time of the as say. However, the assay has short half-life.
Nuclear matrix protein (NMP22)
Cancer-specific nuclear matrix proteins (NMPs) have been identified in colon, breast, bone and urothelium. NMP22 was recognized as a potentia urothelial-specific cancer marker. Malignancy causes these NMPs to be shed from the cell nucleus into the urine by an active form of cell death terme apoptosis”. NMP22 test kit is based on an imm noassay that uses monoclonal antibodies spec NMP22. Several studies reported sensitivity to NMP22 test ranging from 68 % to 100 % without significant difference. Assay specificity differs from 61% to 85%.
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