SALL4 and neoplasm: In xenotransplant models, both of the two Sall4 isoforms—Sall4a (full-length) and Sall4b (alternatively spliced)—expanded hematopoietic cells, supported long-term engraftment, and did not disrupt niche regulation or lead to tumor formation, supporting their utility in achieving clinically significant expansion of human HSCs [22,23].