PAX5 is an important transcription factor in B cell development. Somatic deletions, rearrangements and mutations of PAX5 are seen in approximately 30% of B-ALL. Mutations most commonly include missense and frameshift mutations throughout the gene which typically lead to decreased transcriptional activation by PAX5. A frequent site of mutation is Pro80. Interestingly, a germline variant in PAX5 has been recently described (p.Gly183Ser) that is linked to family history of B-ALL and development of leukemia when associated with 9p deletion(loss of heterozygosity) and retention of the mutant allele in tumor cells; mutations at this codon have also been reported in tumors as a somatic alteration.

This gene is a known cancer gene.

This gene is a known cancer gene.