H19 and neoplasm: However, despite molecular evidence for oncogenic H19 functions in tissue culture systems, tumor suppressive functions have been attributed to H19 in vivo [91]: a hepatocarcinoma mouse model with an H19 knockout developed tumors much earlier than wild-type, a similar model for teratocarcinoma showed decreased tumor growth compared to wild-type embryos, and APCΔ14/+ mice with intact H19 developed fewer polyps than H19 knockouts [92].