PAX5 and acute lymphoblastic leukemia: However, it is unclear if a somatically acquired gene fusion which occurs in humans prenatally during early steps in haematopoiesis, like in the pB-ALL-associated ETV6-RUNX1-translocation, act in a similar manner as an inherited Pax5SNP in the germline because ETV6-RUNX1 [24, 25] and Pax5 [26, 27] are fundamentally different in terms of inheritance and mode of cellular action.