chromosomal instability

Definition of chromosomal instability
National Cancer Institute

chromosomal instability

(KROH-muh-SOH-mul IN-stuh-BIH-lih-tee)
A genomic imbalance that occurs when a cell has an abnormal number of chromosomes. This can be caused by unexpected chromosomal crossover or by the presence of small, extra-chromosomal pieces of DNA.

Source: NCI Dictionary of Cancer Terms