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Chapter 46 : Use of Molecular Biology Methods on Tissues
This chapter provides an overview of several examples of molecular biology applications in this rapidly advancing field. Not all present biomarkers can be detected in tissues that are routinely available in pathology laboratories. There is an ongoing effort to adapt techniques that work well with fresh, unfixed tissues to specimens such as formalin-fixed paraffin-embedded needle biopsy material and cytology smear material. Ligase chain reaction and similar techniques are presently used for the detection of microorganisms in tissues by labeling the oligonucleotides with organism-specific sequences. This process can also be used for detection and quantitation of the expression of specific genes in tissues. The study of familial adenomatous polyposis has demonstrated the presence of adenomatous polyposis coli gene mutations in 5q21. The study of molecular pathways of carcinogenesis has highlighted various molecules that are now therapeutic targets. A relatively simple method of examining hundreds of tissue sections in one experiment is the use of tissue microarrays (TMAs). PCR-based methodologies with the advantage of using fresh, frozen, or formalin-fixed tissues or cells are faster and less labor-intensive and have become the first-line methods in clinical laboratories for clonality testing. The majority of lymphomas and leukemias can be further classified by their characteristic chromosomal lesions. Similar to those associated with hematopoietic malignancies, most genetic abnormalities associated with soft-tissue tumors are chromosomal translocations resulting in novel fusion proteins.
Key Concept Ranking
- B-cell Chronic Lymphocytic Leukemia