THE AMINO-TERMINAL PHOSPHORYLATION SITES OF C-MYC ARE FREQUENTLY MUTATED IN BURKITTS-LYMPHOMA LINES BUT NOT IN MOUSE PLASMACYTOMAS AND RAT IMMUNOCYTOMAS

We sequenced the region encoding the amino-terminal phosphorylation si tes of C-MYC in the Ig/MYC translocation-carrying Burkitt lymphomas (B L), mouse plasmacytomas (MPG) and rat immunocytomas (RIG). Mutations a ffecting the Thr-58 codon or the immediate flanking region were found in seven of the 10 in vitro propagated BL lines. No mutations were fou nd in any of the eight BL biopsies analysed. Germ-line sequences were also found in six in vivo and five in vitro passaged MPCs and in four in vivo transplanted RICs. These findings indicate that mutations in t his region do not represent a general phenomena in Ig/MYC translocatio n-carrying tumours, but may confer growth advantage on BL cells under continuous in vitro propagation.