PTEN and myelodysplastic syndrome: Among the genes which were down-regulated in all subtypes of MDS patients, Runx1 and Pten were selected and focused on, because the former one is known to be responsible for the regulation of early haematopoietic differentiation, while the latter gene known as a tumour suppressor played pivotal role in distinguishing the leukaemic stem cell from the normal haematopoietic stem cell.