found in a majority of t(6:15) plasmacytomas; made up of a 19-amino acid segment termed Pvt-1a (from the Pvt1 (plasmacytoma variant translocation 1) locus), an inserted Trp residue at position 20 followed by the immunoglobulin constant region sequence (Ig-Ck) starting at position 21 to 126; amino acid sequence given in first source; GenBank Z11981