Amplification of exon 4 and the “repeat” region from MM B cells and plasma cells. (A) The region spanning exon 4 was amplified from MM B cells and plasma cells with primer set 6. A single band of 667 bp was detected. Markers are 700, 600, 500, and 400 bp. (B) The “repeat” region of RHAMM was amplified from MM B cells and plasma cells with primer set 7. A single band of 214 bp was detected. Markers are 500, 400, 300, 200, and 100 bp.