[1] UNIV TEXAS,MD ANDERSON HOSP & TUMOR INST,CTR CANC,DEPT TUMOR VIROL,HOUSTON,TX 77030
[2] UNIV TEXAS,MD ANDERSON HOSP & TUMOR INST,CTR CANC,DEPT ENVIRONM BIOL,HOUSTON,TX 77030
[3] ROCHE INST MOLEC BIOL,DEPT CELL BIOL,NUTLEY,NJ 07110
[4] UNIV TEXAS,CTR HLTH SCI,GRAD SCH BIOMED SCI,HOUSTON,TX 77030