Fluorescent In Situ Hybridization

The FISH technique has been carried out to study certain micro deletions that are beyond the resolution of other cytogenetic studies. The marker chromosomes that can not be identified by it's banding pattern, can be studied for various aberrations by applying high resolution FISH. The technique has gained wide acceptance in clinical Cytogenetics and in cancer biology. OncQuest, with its state-of-the-art laboratory performs FISH to locate a number of mutations in a gene including single base deletion. Fluorescent in situ hybridization has set up guidelines to identify aberrations in cancer causing genes as well as tumor suppressor genes. Radio labeled probe binds with the complimentary region of marker gene that is subsequently detected under fluorescent microscope by incorporating radio labeled antibody conjugates. The complex formed is physically mapped under fluorescent microscope to locate micro deletions, identify extra material of unknown origin and to spot subtle or complex rearrangements.

Methodology:

The specimen of the patient is harvested to obtain cells in the metaphase stage of mitosis that are then spread on slides. Banded Fluorescently labeled DNA probes are hybridized to metaphase spreads with specific probes to locate micro deletions & other mutations.