Chromosomal instability (CIN) is a type of genomic instability in which chromosomes are unstable, such that either whole chromosomes or parts of chromosomes are duplicated or deleted. More specifically, CIN refers to the increase in rate of addition or loss of entire chromosomes or sections of them.[1] The unequal distribution of DNA to daughter cells upon mitosis results in a failure to maintain euploidy (the correct number of chromosomes) leading to aneuploidy (incorrect number of chromosomes). In other words, the daughter cells do not have the same number of chromosomes as the cell they originated from. Chromosomal instability is the most common form of genetic instability and cause of aneuploidy.[2]
These changes have been studied in solid tumors (a tumor that usually doesn't contain liquid, pus, or air, compared to liquid tumor),[3] which may or may not be cancerous. CIN is a common occurrence in solid and haematological cancers, especially colorectal cancer.[4] Although many tumours show chromosomal abnormalities, CIN is characterised by an increased rate of these errors.[5]