Volume 7, Issue 1, January 2012
Dr W. S. Wong
Associate Consultant, Department of Pathology, Queen Elizabeth Hospital
Dr. K.F. Wong Chief of Service, Department of Pathology, Queen Elizabeth Hospital
Chronic lymphocytic leukaemia (CLL) is the commonest chronic lymphoproliferative disorder of mature B-cells and affects mainly elderly. It is characterized by the presence of≥5x109/L monoclonal and often CD5+CD23+B-lymphocytes in peripheral blood. Haematogists usually have no problem in reaching the diagnosisas the majority of the cases have classical morphological and immunophenotypic features; however, it is an extremely heterogeneous disease clinically with highly variable clinical course.
Some patients are asymptomatic and do not require treatment while others progress early and require aggressive treatment. A number of clinical and biological parameters as well as molecular biomarkers have been demonstrated to predict the clinical outcome of the disease . Molecular diagnostics has greatly improved the understanding of pathogenesis of CLL by pointing to candidate genes, for example 17p13 deletion, a common genetic aberration seen in CLL, corresponds to a tumour suppressor gene TP53. Moreover, different genetic subgroups have been shown to be associated with different prognosis: poor survival in 17p or 11q deletions and better survival in trisomy 12, normal karyotype or 13q deletion with the best survival found in isolated 13q deletion . Cytogenetic studies may also help in the diagnosis of problem cases with atypical morphology or immunophenotypic profiles.