Using tetrad analysis as well as plasmid shuffling experiments the same study showed that human Pin1 can substitute for yeast Ess1 (see below) both in haploid and diploid cells.4 Depletion of Pin1 from yeast or HeLa cells induced mitotic arrest4 and Pin1 inhibition caused apoptosis in a ras-transformed tumour cell line18 whereas HeLa cells over-expressing Pin1 arrest in G2 phase of the cell cycle. The gene discussed is PIN1; the disease is neoplasm.