Clinical implications of abnormalities of chromosomes 1 and 13 in multiple myeloma

Stratification of patients with multiple myeloma according to clinical severity was attempted by chromosomal analysis of 180 bone marrow specimens from 79 patients. The 79 patients were hospitalized and treated between 1994 and 1999. Abnormalities of chromosome 1 were detected at the initial medical examination in 8 (10%) of the 79 patients and were found during follow-up in additional 3 patients. Abnormalities of chromosome 1 were often detected in IgA (4/17) and IgD (2/4) multiple myeloma, while detection in IgG myeloma was relatively rare (4/42). The relevant break points were 1q12 in 5 patients and 1q42 and 1q21 in 3 patients, while 3 patients had trisomy 1. Deficiency of the long arm of chromosome 13 was detected in 6 patients, and this was believed to imply a prognosis. The long arm was completely deleted in 2 patients and part of the arm (13q10-14) was deleted in 4 patients. It is interesting that all 6 patients had concomitant abnormalities of chromosome 1. Although the initial response to treatment of patients having abnormal chromosomes 1 and 13 was comparable to that of patients having other chromosomal abnormalities or patients who were karyotypically normal, the median survival time was only 18 months (p < 0.02). Consequently, aggressive treatment such as early stem cell transplantation and so on is needed to improve their survival.