t(9:14) translocations involving the PAX-5 andIgH loci. A schematic diagram depicts the 5′ region of the PAX-5 gene, the J_H-to-C_μ region of the IgH locus and the corresponding translocation breakpoints present on the derivative chromosme 14 in the lymphomas of patients KIS-1,8 1052,9 and MZL-1 (this study). The PAX-5 expression level and the translocation breakpoint relative to the antisense promoters in the immunoglobulin Sμ region have not been mapped in patient 1025,9 and hence it is not known at present whether promoter replacement as described for patient MZL-1 may be a molecular mechanism for PAX-5 gene deregulation in this case. The position of the translation start codon at the very 3′ end of PAX-5 exon 1B is indicated by ATG.