RUNX1 and Down syndrome: However, increased expression of RUNX1 can also be oncogenic: amplification of the chromosome region 21q that contains the RUNX1 gene (for example, chromosome trisomy 21 in Down syndrome) has been observed in ALL from the B lineage precursors and AML; high levels of RUNX1 expression have also been found in various epithelial neoplasms (including skin cancer, endometrioid tumor) [4].