Chromosomal alterations associated with lower disease-specific survival rates in MF. Patients were divided based on the loss of an MCR on 9p21, or gain of MCRs on 8q24.3 or gain of 1q21-22. Actuarial survival rates were calculated from the date of biopsy using the Kaplan-Meier technique. The log-rank test was used to analyze differences between survival rates.