○ Chromosome segregation not affected, but minor fraction shows mild cohesion defects. No early tumor onset.○ Trilineage hematopoiesis and extramedullary erythropoiesis is affected.○ Proliferative cells in bone marrow, lymph nodes, spleen are affected.○ T cells count decrease in peripheral blood and spleen; monocytes and neutrophils increase○ STAG1 deletion has no organ malformation, but STAG2 deletion has widespread heart defects, and lethality at E9.5. Here, STAG2 is linked to neoplasm.