Comparison of B-cell and plasma cell RHAMM. RHAMM cDNA fragments were amplified from MM B cells and BM plasma cells by RT-PCR with RHAMM-specific primers and subsequently cloned and sequenced. The nucleotide sequences of the RHAMM fragments were aligned to generate the sequence of B-cell RHAMM^FL and BM plasma cell RHAMM^FL. The 48-bp deletion and the 147-bp deletion that characterize RHAMM⁻⁴⁸ and RHAMM^−147,respectively, are marked in bold lowercase. The 2 ATG start codons (base 18-20 and base 363-365) and TAA stop codon (base 2197-2199), previously described for breast RHAMM, plus the 2 HA-binding domains are underlined.