Molecular pathology and Cytogenetics are vital and growing divisions in the Department of Pathology and Laboratory Medicine.
Among the anatomic specialties, pathologists already are using molecular assays for detection of chromosomal recombinations for diagnosis and prognosis of various neoplastic entities. In clinical pathology specialties, genetics and infectious disease diagnosis are prominent as molecular-based technology redefines these areas. Thrombophilia is evaluated by molecular probe technology, and lymphoma/leukemia is studied molecularly for diagnosis. The molecular biology of these afflictions already dictates the treatment of these patients. Within the field of microbiology, numerous probes and amplification assays are available for the rapid diagnosis of bacteria and viruses and emerging microbes, such as West Nile Virus and the SARS associated viruses.
For the resident, the required Molecular Pathology Rotation consists of a one month introduction to the specialty, during which residents learn or review core concepts of DNA and RNA related technologies, such as probe techniques, PCR, TMA, microarray and other molecular tools. Residents present molecular cases at conferences and may carry out research projects of interest to them. Residents may spend several extra months in Molecular Diagnostics if they choose. There are opportunities to develop assays, participate in cancer, viral or even viral immunologic diagnosis and research, depending on individual interests and motivation.
The Cytogenetics Laboratory at Cedars-Sinai uses standard or specialized banding techniques, or molecular cytogenetic techniques for the evaluation of both congenital and acquired chromosome abnormalities that have an impact on phenotype, reproduction and malignancy. The Cytogenetics Laboratory provides the full range of state-of-the-art services, including classical cytogenetic analysis, high-resolution chromosome analysis and molecular cytogenetics (fluorescence in situ hybridization, or FISH) on a variety of specimen types, such as blood, bone marrow, lymph nodes, solid tumors, tissue (e.g., POC or skin), amniotic fluid cells and chorionic villi or placenta.
Cytogenetic evaluation can be used to detect chromosome abnormalities responsible for birth defects and developmental problems. Chromosome abnormalities are observed in about four to eight percent of children with congenital malformations, as well as at least 13 percent of those with congenital heart defects. Chromosome abnormalities also are seen in patients with mental retardation and developmental delay, as well as a small proportion of children with autism. Some anomalies of sexual development can be due to chromosomal abnormalities.
When cells become neoplastic, they often acquire chromosome abnormalities not seen in the normal cells, which can be of value in making a diagnosis, predicting prognosis and following the course of various leukemias and other cancers. The World Health Organization uses cytogenetic data as part of the criteria for classifying leukemias and lymphomas. More than 70 percent of patients with leukemia display acquired chromosome abnormalities in their leukemic cells, and between 80 and 90 percent of malignant lymph nodes will contain chromosomally abnormal cells. If the disease responds to treatment, the abnormal clone is usually lost, and only chromosomally normal cells will be detected.
Similarly, relapse or disease progression will be associated with the presence of chromosome abnormalities and increasing complexity of the abnormalities seen. Thus, cytogenetic studies can be used to monitor the course of the disease. Hematological malignancies and some solid tumors can be assessed by evaluation of appropriate cultures of peripheral blood (leukemic blood), bone marrow, lymph nodes or other tumor biopsy tissue. Standard cytogenetic analysis and FISH techniques are utilized to fully elucidate the cytogenetic diagnosis.
