CYTOGENETIC FINDINGS IN 200 PATIENTS WITH MULTIPLE-MYELOMA

Cytogenetic studies were performed on 200 consecutive patients with mu ltiple myeloma and related disorders. Structurally or numerically abno rmal clones were found in 63 patients (32%), including 8 of 45 untreat ed patients (18%), and 55 of 155 treated patients (35%). The abnormal karyotypes generally showed numerous numerical and structural aberrati ons and in some patients multiple abnormal clones. The most striking f eature of patients with hyperdiploid karyotypes was the finding of con sistent recurring trisomies for chromosomes 3, 5, 7, 9, 11, 15, 19, an d 21, cosegregating together in many cases. Monosomy for chromosome 13 was the most common chromosome loss, occurring in 18 abnormal patient s (29%), while interstitial deletions involving band 13q14 occurred in an additional 9 patients, indicating a loss of all or part of chromos ome 13 in a high percentage of patients with abnormal karyotypes (43%) . Structural aberrations of chromosome 1 were most frequent, occurring in 30 of 63 patients (48%), and involved almost equally the short and long arms. The single most frequent chromosome breakpoint involved ba nd 14q32 and was found in 21 patients (33%), including 11 patients wit h a 14q+ chromosome, 8 with t(11;14)(q13;q32), and 2 with t(8;14)(q24; q32).