CCNB1 and neoplasm: However, even though these early results turned out to be in accordance with the finding that mice in which the ZC3HC1 gene had been knocked out by homologous recombination are viable [104,105], the alleged role for ZC3HC1 in regulating cell cycle progression via controlling cellular levels of CCNB1 was recurrently reported to manifest itself in a range of aneuploid human tumour cell lines and other types of immortalised human cells [104,106,107,108].