The sequence of the exon 1/intron 1 boundary region of the MYC gene was determined in two diffuse large cell lymphomas (DLCL), one with t(8;14) (q24;q32) and the other with t(8;22) (q24;q11). Both tumors had multiple mutations in this region. Also, both tumors had mutations in the protein binding site in intron 1, which is a frequent target for mutational inactivation in endemic Burkitt's lymphoma (eBL). The translocations at 8q24, and multiple mutations in the exon 1/intron 1 boundary region, are reminiscent of similar findings in eBL. The same underlying oncogenic event that occurs in most eBLs is thus found in some DLCLs.