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Decoding cancer: How does CISH help doctors predict patient survival rates?
Accurate genetic testing technology plays a vital role in cancer diagnosis and prognosis. With the advancement of science and technology, many new technologies have emerged one after another, among which the highly competent one is chromosomal in situ hybridization (CISH). Since its advent in 2000, this technology has quickly become an important tool in clinical diagnosis, especially in the assessment of HER-2/neu gene amplification, which has added many possibilities.
What is CISH?
Chromosome in situ hybridization (CISH) combines the staining signal detection methods of immunohistochemistry (IHC) and in situ hybridization. The main advantage of CISH over traditional fluorescence in situ hybridization (FISH) is that it is more practical because it can be performed under a brightfield microscope, whereas FISH requires an expensive and complex fluorescence microscope.
Technical principles and processes
The design principles of CISH are similar to FISH, with the main difference being the labeling and detection methods. Most CISH probes are labeled with biotin or deoxynucleotidase and are detected by brightfield microscopy after processing.
In the application of CISH, the design of probes is challenging and usually requires extraction, amplification and labeling from bacterial artificial chromosomes (BAC) to ensure that they can accurately bind to the target DNA.
Comparison with other technologies
Although FISH is considered the gold standard for detecting chromosomal abnormalities, CISH has a sensitivity of 97.5% and a specificity of 94% for HER-2/neu gene amplification. The consistency between the two is as high as 94.8%, showing that CISH is as reliable as FISH.
It is worth noting that the advantages of CISH are its simplicity and cost-effectiveness, which makes long-term sample storage and subsequent testing easier for clinical laboratories.
Medical applications of CISH
CISH is commonly used to assess the gene amplification status of HER-2/neu in breast cancer samples. Studies have shown that HER-2/neu gene amplification is significantly associated with high mortality and poor prognosis in breast cancer patients. Clinically, the monoclonal antibody trastuzumab has good efficacy in tumors that overexpress HER-2/neu, so it is extremely important to determine the receptor status before initiating cancer treatment.
CISH can also be used to detect other chromosomal rearrangements and fusions. For example, in lung cancer, the genetic fusion of the ALK tyrosine kinase domain to EML4 is a clinically relevant subpopulation that can be effectively treated with ALK inhibitors. treat.
Variations of new technologies
Besides CISH, there are some variants such as silver-enhanced in situ hybridization (SISH) and dual CISH (DuoCISH). SISH generates detection signals through silver deposition, allowing for improved visualization in some cases. DuoCISH can use two probes on the same glass carrier at the same time to detect different genes, which helps distinguish gene amplification from chromosomal aneuploidy.
Conclusion
CISH, as an emerging genetic testing technology, not only improves the accuracy of cancer diagnosis and treatment, but also enables more accurate prediction of patient survival. However, in future oncology practice, how to comprehensively apply these technologies to improve the effectiveness of personalized treatment will be an important issue worth pondering?
