Cytogenetic and FISH Laboratory

Conventional Cytogenetic and FISH Tests

By means of Conventional cytogenetic and Fluorescent In Situ Hybridization (FISH) methods, the structures called chromosomes in which the genetic information of each cell are kept are structurally and numerically analyzed (karyotyping). Hematologic cancers being in the first place, the chromosomal disorders that are determinants on diagnosis and follow ups of diseases are defined with karyotyping.

How is the test performed:

The bone marrow samples are reproduced for 24 hours in a sterile culture media that enables simultaneous reproduction of cells (synchronous culture). Then the collected cells are taken onto the lamina, analyzed and the chromosomes are enabled to senesce in an appropriate media. The chromosomes spreading by expanding are dyed (Giemsa-Trypsin banding method) and prepared for microscopic examination. The samples prepared in this way are examined structurally and numerically in the image analysis system and karyotyping is performed.

In FISH method, similar to the cytogenetic test, synchronous culture is generated with bone marrow samples. Following this procedure, the cells are collected and DNA particles (probes), marked with fluorescent that recognize the DNA regions to be analyzed, are applied. The probes are waited to connect to DNA and the unconnected particles are removed by washing. The cell nucleuses are also dyed (Dapi staining) and analyzed on image analysis system. Cytogenetic and FISH results are reported in compliance with "International System for Human Cytogenetic Nomenclature".

Consideration for cytogenetic and FISH analyses

Cytogenetic and FISH tests are performed through bone marrow samples. The samples that are taken into the heparin containing injectors or tubes (green covered) in sterile conditions should be delivered to the laboratory of Basic Oncology Subdivision within the shortest time, in order to minimize the cell loss. In addition, it is necessary for the bone marrow samples not to include clots, for the accuracy of test. Thus, after the sample is taken, it is recommended to turn the injector up and down for a few times, for the sample to be mixed with heparin. Otherwise the sample is not admitted.

Conventional cytogenetic result reports within 2-3 weeks and FISH reports within 10 days, can be received from the secretariat of division that the patient is examined by means of hospital system or from the Secretariat of Basic Oncology Subdivision.