Lymphoid leukaemia: a look at the genetics of proliferation

Leukaemia is a cancer specifically of white blood cells (leucocytes). In common with the other formed elements in blood, white cells are derived from the multipotential haemopoietic stem cell in bone marrow, and leukaemia is characterised by the accumulation of malignant white cells in bone marrow and blood, at the expense of normal blood cell production.

There are four main leukaemia types, which define both the speed of disease progression (acute or chronic) and the type of white cell malignantly transformed (myeloid or lymphoid), and these are chronic myeloid, chronic lymphoid (both slowly progressive), acute myeloid and acute lymphoblastic (both rapidly progressive).

Of the four types, acute lymphoblastic leukaemia (ALL) is the least common overall but the most common to affect children. In fact, ALL is the most common cancer of any type to occur in childhood, and accounts for 85% of all cases of childhood leukaemia, the peak incidence of ALL being between the ages of three and seven years.