Molecular abnormalities in B-cell chronic lymphocytic leukaemia

Prediction and preliminary validation of oncogene regulation by miRNAs

Background

MicroRNAs (miRNAs) are one of the most abundant groups of regulatory genes in multicellular organisms, playing important roles in many fundamental cellular processes. More than four hundred miRNAs have been identified in humans and the deregulation of miRNA expression has been also shown in many cancers. Despite the postulated involvement of miRNAs in tumourigenesis, there are only a few examples where an oncogene or a tumour suppressor has been identified as a miRNA target.

Results

Here, we present an in silico analysis of potential miRNA- oncogene interactions. Moreover, we have tested the validity of two possible interactions of miRNAs with genes related to cancer. We present evidence for the down-regulation of c-MYC, one of the most potent and frequently deregulated oncogenes, by let-7 miRNA, via the predicted binding site in the 3'UTR, and verify the suppression of BCL-2 by miR16.

Conclusion

In this work both bioinformatic and experimental approaches for the prediction and validation of possible targets for miRNAs have been used. A list of putative targets for different oncomirs, validation of which would be of special interest, is proposed and two such interactions have been experimentally validated.

The clinical and epidemiological burden of chronic lymphocytic leukaemia

The purpose of this literature review was to identify and summarize published studies describing the epidemiology and management of chronic lymphocytic leukaemia (CLL). Chronic lymphocytic leukaemia represents 22-30% of all leukaemia cases with a worldwide incidence projected to be between < 1 and 5.5 per 100,000 people. Australia, the USA, Ireland and Italy have the highest CLL incidence rates. Chronic lymphocytic leukaemia presents in adults, at higher rates in males than in females and in whites than in blacks. Median age at diagnosis is 64-70 years. Five-year survival rate in the USA is 83% for those < 65 years old and 68% for those 65 + years old. Hereditary and genetic links have been noted. Persons with close relatives who have CLL have an increased risk of developing it themselves. No single environmental risk factor has been found to be predictive for CLL. Patients are usually diagnosed at routine health care visits because of elevated lymphocyte counts. The most common presenting symptom of CLL is lymphadenopathy, while difficulty exercising and fatigue are common complaints. Most patients do not receive treatment after initial diagnosis unless presenting with clear pathologic conditions. Pharmacological therapy may consist of monotherapy or combination therapy involving glucocorticoids, alkylating agents, and purine analogs. Fludarabine may be the most effective single drug treatment currently available. Combination therapy protocols have not been shown to be more effective than fludarabine alone. As no cure is yet available, a strong unmet medical need exists for innovative new therapies. Experimental treatments under development include allogeneic stem cell transplant, mini-allogeneic transplants, and monoclonal antibodies (e.g. alemtuzumab against CD52; rituximab against CD20).