Clinical impact of molecular diagnostics in low-grade lymphoma.

Molecular diagnostics in low grade B cell lymphoma is currently based on polymerase chain reaction (PCR) detection of lymphoid clonality or of molecular (onco)genetic markers that result from chromosomal translocations. The former is based on detection of clonal immunoglobulin (Ig) and/or T cell receptor (TCR) rearrangements, which can be used for distinguishing between malignant and reactive lymphoproliferation, for staging, for comparison of diagnostic and relapse material and for minimal residual disease assessment. Informativity has risen with the development of improved, standardised DNA-based Ig/TCR strategies but remains dependent on tumour subtype, largely as a function of the rate of IgH somatic mutation.