POU5F1 and neoplasm: The results are compatible with a situation wherein the existing haemangioblastomas should not proliferate due to decrease in proangiogenic genes (Epo and VEGF), a decrease in the expression of tumour progression genes, Sox-2 and Oct4 and an increase in proapoptotic Bax. All cells in patients are heterozygous for the Vhl gene, with the exception of cells from haemangioblastomas (Vhl−/−).