What is "kataegis"

In molecular biology kataegis describes a pattern of localized hypermutation identified in some cancer genomes. The term kataegis is derived from the ancient Greek word for "thunder", καταιγίς (kataigis). Regions of kataegis have been shown to be colocalised with regions of somatic genome rearrangements. The base mutations in these regions were found to be almost exclusively cytosine to thymine in the context of a TpC dinucleotide. It has been hypothesised that an enzyme of the APOBEC family is responsible for the process of kataegis. The direct link between the APOBEC deaminases and kataegistic clusters of mutations was recently obtained by expressing hyperactive deaminase in yeast cells. More recent evidence has linked the overexpression of the family member APOBEC3B with multiple human cancers, highlighting its possible contribution to genomic instability and kataegis.