Chromosome Analysis, Lymphoid Tissue
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Chromosomal abnormalities play a central role in the pathogenesis, diagnosis, and monitoring of treatment of many hematologic disorders.
The observation of a chromosomally abnormal clone is consistent with a clonal neoplastic process.
Certain chromosome abnormalities can help classify the type of lymphoma. For example, t(14;18)(q32;q21.3) involving the IGH and BCL2 genes is usually indicative of a follicular lymphoma. A translocation between C-MYC and IGH genes or a t(8;14)(q24.1;q32) are both associated with Burkitt's lymphoma.
Cytogenetic studies often can help distinguish between B-cell and T-cell disorders. Structural abnormalities involving breakpoints at any immunoglobulin locus is consistent with a B-cell disorder; structural abnormalities involving breakpoints at a T-cell receptor site are usually associated with a T-cell disorder.
Assisting in the classification of certain cases of lymphoma
The observation of a chromosomally abnormal clone is evidence of a clonal neoplastic process.
Certain chromosome abnormalities also may be associated with certain morphologic classifications. However, a normal karyotype does not eliminate the possibility of a neoplastic process.
On rare occasions, the presence of an abnormality may be associated with a congenital abnormality that is not related to a malignant neoplastic process. Follow-up with a medical genetics consultation is recommended.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
-Lack of viable cells
-Cell death due to failure to transport tissue in appropriate media
-Excessive transport time
-Exposure of the specimen to temperature extremes (freezing or >30 degrees C)
-Specimen has been stored or treated with formalin or another fixative or is paraffin-embedded
-Normal cells in the specimen may grow better in culture than tumor cells and interfere with the cytogenetic studies
-Mitogen-stimulation of normal lymphocytes rather than malignant lymphocytes, in the culture process
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
46,XX or 46,XY. No apparent chromosome abnormality.
An interpretive report will be provided.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Pierre RV, Dewald GW, Banks PM: Cytogenetic studies in malignant lymphoma: possible role in staging studies. Cancer Genet Cytogenet 1980;1:257-261
2. Dewald GW, Jenkins RB: Cytogenetic and molecular genetic studies of patients with monoclonal gammopathies. In Neoplastic Diseases of Blood. Second edition. Edited by PH Wiernik, GP Canello, RA Kyle, CA Schiffer. New York, Churchill Livingstone, 1991, pp 427-438