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Cytogenetics of Solid Tumors
The
Karyotypic abnormalities in solid tumors are often quite complex.
They constitute less than one-third of all cases with an abnormal
karyotype reported in the literature. However there are cytogenetic
aberrations especially balanced translocations which occur with
remarkable specificity in distinct tumor sub types. Balanced simple
disease specific changes are seen in about 20% of mesenchymal tumors
and less than 5% of epithelial neoplasms. Specific translocations
and gene amplifications are used as markers for diagnosis and prognosis
in mesenchymal and epithelial neoplasms. INDICATIONS: Chromosomal
analysis can be performed on all tumor specimens (benign and malignant).
List
of Neoplasms ( Cytogenetic changes are specific and consistent in
certain tumor types) Mesenchymal
Neoplasms Rothmund-Thompson Syndrome
SAMPLE REQUIREMENTS: The excision of a tumor mass is performed surgically. A pathologist routinely examines the tissue. The size of the sample will vary depending on the size of the actual tumor.
SPECIMEN HANDLING: Place tissue in a sterile container or a centrifuge tube with tissue culture media (3X) provided by the laboratory. Containers must be tightly capped to prevent leakage. If media is not available, then place in sterile gauze moistened with water and deliver immediately. DO NOT SUBMERGE THE SPECIMEN IN SALINE OR WATER. Tumors in media may be stored in refrigerator for up to three days. Specimens that are dry, frozen, irradiated, in saline and formaldehyde or stored for more than three days may not grow. Tissues not collected sterilely may get contaminated. A tissue culture charge for handling these specimens will result. Call the laboratory for a pick up or mail via Federal Express overnight. In case of late or weekend collection, store specimen in refrigerator. Do not freeze. Tissue not in 3X media must be delivered immediately. Call the laboratory for pick up at the earliest convenience. PROCEDURE: The tissue is processed for suspension and in situ cultures. Loose cells are released from the tissue by gently tapping with a scalpel. The cell suspension is set up in culture in media without the mitotic stimulant phytohemaglutinin (PHA) and incubated for 24 hours at 37°C. Ethidium bromide is used simultaneously with colcemid to improve chromosome morphology. Harvest is performed by routine methods. The tissue is digested enzymatically to dissociate into a single cell suspension. The cells are plated onto several dishes according to cell density and viability. Cultures are maintained at 37°C until ready to harvest. Colcemid is added to initiate harvest. Harvest is performed by routine methods. INTERPRETATION: Twenty metaphase cells are analyzed under the microscope whenever possible. Two karyotypes are prepared from the mainline, and one from each sideline. RESULTS: Results are presented according to the International System for Human Cytogenetic Nomenclature (ISCN 2005). Full explanation of the karyotype is provided and a short summary is written for each abnormal result.
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