RAD21 and neoplasm: As bi-allelic mutations of Rad21 in mouse [28] and rad21a in zebrafish (https://zfin.org/ZDB-GENE-030131-994) lead to embryonic lethality, we used zic:rad21ahi2529Tg/+ heterozygous to generate tumor models with reduced rad21a levels (named rad21;RAS).