The authors review the literature concerning monoclonal B-cell lymphocytosis, and the occurrence of chromosomal translocations t(14;18) and t(11;14), NPM-ALK fusion gene, JAK2 V617F mutation, BCR-ABL1 fusion gene, ETV6-RUNX1(TEL-AML1), MLL-AF4 and PML-RARA fusion gene in healthy individuals. 