Tumor CytoGenomics Laboratory Clinical Services 

Chromosome abnormalities usually occur when there is an error in mitosis, the process by which one cell divides into two duplicate cells. In humans, chromosome abnormalities are divided into two groups: congenital abnormalities, which are inherited from parents, and acquired abnormalities, associated with cancer. 

Chromosomes are stained so they can be viewed. Through a microscope, chromosomes resemble pairs of banded strings (called chromatids) that are attached at one point (called the centromere), forming a four-arm structure. A map of the human cell’s 46 chromosomes, called a karyotype, is created to help identify abnormalities in either the structure or the number of chromosomes. 

Thousands of chromosomal abnormalities have been associated with cancer. These aberrations are highly variable in different cancers, creating equally variable phenotypic effects. Cancer cells generally gain multiple types of chromosomal aberrations during tumor progression, including rearrangements, deletions, and duplications. Chromosomal rearrangements can lead to cancer either by forming a hybrid gene or by causing dysregulation of a gene. Hybrid genes form by fusion of portions of two different genes at the chromosome rearrangement breakpoints of two or more chromosomes; these rearrangements can be detected using a technique called fluorescence in situ hybridization (FISH). Sometimes, the same hybrid gene is present in multiple types of cancers, indicating that such genes might initiate cancer progression in a variety of tissues. Dysregulation of normal genes can contribute to the conversion of normal cells into cancerous cells. 

Learn more about the clinical tests we perform.  

Learn more about the disease-specific genes we test in our Laboratory.