Fluorescence in situ Hybridization (FISH)
Cell nuclei from urine appear red (chromosome 3), green (chromosome 7), yellow (chromosome 9), and blue (chromosome 17) after
hybridization with FISH assay probes. (Photograph courtesy of Kerstin Juniker, Ph.D.)
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The FISH technology platform is a system in which genes and chromosomes are probed by fluorescent-labeled DNA and then illuminated
to allow for clearer identification. It has been shown that by identifying abnormalities in chromosomal DNA, clinicians can
effect better treatments.
Research work at the University of Jena first noted that FISH would be useful in detecting bladder cancer. Guttman noted that
the sensitivity of the FISH assay was superior in all stages of disease compared with cytology, and it correctly identified
all invasive tumors (pT2-pT4).13
The FISH assay is a multi-color kit that uses four probes to detect aneuploidy for chromosomes 3, 7, and 17 and loss of the
9p21 locus in cells from voided urine samples. To perform the test, cells are fixed onto glass slides by centrifugation or
pipetting for identification of the 25 nuclei that are most abnormal morphologically according to DAPI counterstaining. Each
of the selected cells are classified into one of three groups based on enumeration of signals for the four chromosome targets,
and the specimen is determined to be negative or positive for tumor according to the classification results.
On January 25, 2005 FDA approved Abbott Laboratories' UroVysion DNA probe-assay for use as an aid in the initial diagnosis
of bladder cancer in patients with hematuria (blood in urine) and suspected of having bladder cancer.14 With this approval, UroVysion represents the first gene-based test available for both diagnosis and monitoring of bladder
cancer recurrence. The test is designed to detect genetic changes in bladder cells in urine specimens FISH. Names get confusing
because the FISH products are researched and marketed by a subsidiary named Vysis and not directly by Abbot. In addition to
UroVysion, FISH is utilized in an FDA-approved device, PathVysion, to quickly identify which patients with late-stage breast
cancer are suitable candidates for Herceptin therapy. Abbot scientists are also exploring FISH's diagnostic capabilities for
cervical, esophageal, melanoma, and hematological cancers.
Teamed up with Vysis to solve cancer problems is Applied Imaging Corp., which has received 510(k) clearance from FDA to market
its Ariol Her-2/neu FISH application.15 This is designed to detect Her-2/neu gene amplification in breast cancer biopsy samples
via FISH. The application complements and completes the breast cancer panel on the Ariol system, which now includes 510(k)
cleared assays for Her-2/neu Immunohistochemistry (IHC), Her-2/neu FISH, Estrogen Receptor, and Progesterone Receptor. The
Ariol Her-2/neu FISH application assists in the analysis of a complex test that is an important factor in the evaluation and
selection of certain breast cancer patients for Genentech's Herceptin (trastuzumab) therapy.
HPLC
High-performance liquid chromatography is similar to larger-scale liquid chromatography but is set up to be more powerful.
The resin particles in the stationary phase are smaller to increase the number of plates and the loading is quite low and
there are many choices of the mobile phases.
R&D Magazine selected the Corona CAD (Charged Aerosol Detector) for its prestigious 2005 R&D 100 Award.16 The Corona is a breakthrough, universal detector technology for HPLC (High Performance Liquid Chromatography). The Corona
CAD is a breakthrough device because it is the only available technology to simultaneously offer the following benefits in
one, rugged, cost-effective, easy-to-use instrument:
- Excellent sensitivity
- Wide dynamic range
- Superior reproducibility
- More consistent response
- Broad applicability
- Intuitive operation
Immunoassay
Antibodies detect the presence of certain molecules in a sample. Monoclonal antibodies (Mabs) bind very specifically to their
targets at low concentrations. These Mabs must be tagged in some way to permit measurements. Sporadic news is available about
this topic as many companies make products in this wide-ranging field. Enclosed are three from 2005.
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