Gain of 20q11.21 is very frequent in human embryonic stem cell (hESC) lines, human embryonal carcinoma cell lines and some teratocarcinomas44, and may confer protection against apoptosis as a result of BCL2L1 overexpression45,46, as well playing a role in malignant transformation45. Here, BCL2L1 is linked to embryonal carcinoma.