Diagnostic Tests for Breast Cancer

Breast cancer remains the only major cancer where inevitable treatment is routinely carefully by definite predictive factors. Currently, commercial predictive technology is divided into four major platforms, immunohistochemical (Ihc) testing, fluorescent in situ hybridization techniques (Fish), genomic diagnosis and quantitative immunofluorescence. Tests based on immunohistochemistry (Ihc) and fluorescent in situ hybridization techniques (Fish) currently dominate the breast cancer diagnostic testing landscape. In this context, these two techniques are most often used to rate Her-2 or hormone-receptor status. Evaluations of test results allow clinicians to accurately elect patients likely to benefit from the corresponding therapy. This shop is currently dominated by large, established clubs offering Fda beloved products.

At this time genomic assays are most often used to conclude cancer relapse and recurrence, although extension into predictive assays is underway. These laboratory based assays are currently the domain of small and mid-level companies. Tests using fluorescently tagged antibodies to portion amounts of proteins associated to definite drug performance have recently entered the market. These tests can help physicians conclude which drugs are most likely to be efficient for a definite patient.

Microscope

Immunohistochemical Testing

Ihc is the process of localizing proteins in cells of a tissue section utilizing the principle of antibody binding to definite antigensGenerally, Ihc tests have Fda approval and are sold in the relatively low price range of 0 - $ 400. These tests are performed routinely in many diagnosis laboratories. The prognostic value of Ihc is well established for Her-2 and Estrogen Receptor (Er), but is not established as a predictor of the efficacy of cytotoxic drugs. Furthermore, there has been vast business concern over the reproducibility of Her-2 /neu detection from lab to lab, that affects the accuracy of the test. For examples, both the American community of Clinical Oncology and the College of American Pathologists recite the interpretation of Ihc results as "somewhat arbitrary" and found that results from "as many as 15 - 20 % of the assays may be incorrect."

Fluorescent in situ Hybridization Techniques

Fish is a cytogenetic technique that can be used to detect and localize the proximity of definite Dna sequences on chromosomes. This technology is often used in conjunction with Ihc to conclude Her-2 expression and has recently been applied to hormone receptor status. As with immunohistochemistry, these tests are performed routinely in many diagnosis laboratories. The marketed technologies again commonly have Fda approval and shop in the 0 - 0 range. A amount of retrospective clinical trials have recommend that Fish is more accurate in predicting a inevitable benefit from Herceptin therapy. However, inevitable drawbacks are also associated with Fish analysis. For instance, hybridization cannot be achieved in all tumors. In addition, the results of this formula can vary considerably if the assay is not standardized, and is thereby dependent on the skill of the pathologist.

Genomic Assays

More recently, a amount of diagnostic tests based on the gene expression in breast cancer tissue have entered the expanding shop for breast cancer diagnostics. These tests are commonly centralized laboratory assays that utilize statistical data diagnosis and algorithms to deliver results. Genomic assays gawk the expression of a unique set of genes that may indicate the recurrence of cancer or possible response to treatment. Genomic assays are currently used primarily to predict recurrence of breast cancer and are being extended to indications of hormonal and Her-2 receptor status. Competition in this segment is based on introduction of assays using separate and more numerous gene sets. The attention of current explore is on the use of this technology in the predictive mode for response of breast and other cancers to chemotherapeutic drugs.

The leader in the current genomic Rt-Pcr shop is Genomic Health, which offers the Oncotype Dx assay. This test analyzes the expression of 21 genes and is currently geared towards predicting the recurrence of breast cancer. Using the microarray platform, Agendia offers the Mammaprint assay. This is a 70 gene assay that also predicts recurrence of breast cancer. Price for theseassays runs in the 00/test range. Although genomics are a promising technology, inevitable limitations exist. These assays are, in general, applicable to only a subset of cancer patients and are far from being standardized. They demonstrate considerable variability and, since tissue is homogenized for this type of analysis, all sense of tissue topography and heterogeneity is lost.

Quantitative Immunofluorescence

Quantitative immunofluorescence uses antibodies tagged with fluorescent dyes to detect specified proteins in breast cancer tissue. The antibodies bind to their targets, which are associated to the performance of inevitable chemotherapy drugs. The resulting fluorescence can be measured, or quantitated, with a digitized microscope. The amount of fluorescence detected can be used to indicate which drug treatment will be most effective. Up-to-date studies have recommend that quantitative immunofluorescence results in increased test sensitivity and reproducibility. A diagnostic test based on quantitative fluorescence is currently offered commercially by Ccc Diagnostics. The cost of a test panel for commonly used treatments is 00 and is covered by many major guarnatee companies.

There are some technical drawbacks to this formula such as photobleaching of the sample and high background. But if the test is properly controlled quantitative immunofluorescence offers a high degree of accuracy and repeatability. Futhermore, since this technology assays proteins in the cell, it may present a great picture of how cells will acknowledge to a given drug. Predictive diagnostic tests for breast cancer have not been fully approved for choosing treatment. As these tests become more widely utilized, they will form the basis of individualized treatment for breast cancer patients.

Diagnostic Tests for Breast Cancer

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