A genetic alteration refers to any change that occurs in the DNA sequence of an organism's genome. These changes can be caused by a variety of factors, such as exposure to certain chemicals or radiation, errors during DNA replication, or inherited mutations.

Genetic alterations can have a wide range of effects on an organism's biology, including its physical traits, susceptibility to certain diseases, and response to different treatments. Some genetic alterations may have no effect, while others may be harmful or even lethal.

In the context of cancer, genetic alterations are a major driver of tumor development and progression. Cancer cells often accumulate mutations and other genetic alterations that disrupt the normal regulation of cell growth and division, allowing them to grow and multiply uncontrollably. Identifying and targeting specific genetic alterations in cancer cells is a key strategy for developing more effective cancer treatments.