FOXP1 and precursor B-cell acute lymphoblastic leukemia: While PAX5-FOXP1 is found in fewer B-ALL cases, it is still a recurrent translocation that connects almost the entire FOXP1 transcription factor sequence to the N-terminal PAX5 sequence.[32,34] PAX5-ETV6 and PAX5-FOXP1 are examples of chimeric PAX5 fusion proteins, which are multi-domain transcription factors.