Combining information on chromosomal aberrations del(17p13), t(4;14), and +1q21 (> 3 copies) with ISS score allows stratification of MM patients undergoing high-dose chemotherapy followed by autologous SCT. The combination of the presence or absence of del(17p13), t(4;14), and +1q21 (> 3 copies) with the ISS score allowed stratification of patients into 3 distinct groups: low-risk, high-risk, and intermediate-risk (all remaining patients), representing 33%, 49%, and 18% of patients, respectively.