No Adverse Impact of 13q14 and P53 Deletion, t(4;14)(p16;q32) or Overrepresentation of CMYC(8q24) as Detected by Fluorescence In Situ Hybridization on Outcome in Patients with Multiple Myeloma Following Dose-Reduced Allogeneic Stem Cell Transplantation

Deletions of chromosome bands 13q14 and 17p13 (P53) as well as t(4;14)(p16;q32) or overrepresentation of CMYC are known to be adverse prognostic factors for time to progression (TTP) and overall survival (OS) in myeloma patients receiving conventional or high-dose chemotherapy followed by autologous stem cell transplantation. We investigated the impact of these chromosomal abnormalities as detected by fluorescence in situ hybridization combined with immunofluorescent cytoplasm immunoglobulin staining (cIg-FISH) on outcome after dose-reduced melphalan/fludarabin based allogeneic stem cell transplantation (SCT) in 64 patients (pts) with multiple myeloma (MM). Median age was 52 years (34 – 67 ys.), 38 patients were male, 26 female. 45 pts received stem cell graft from an unrelated donor and 19 pts from HLA-identical sibling. Deletion of 13q14 was found in 35 out of 64 pts (55%), P53 deletion in 7 out of 64 pts (11%), t(4;14)(p16;q32) in 11 out of 56 pts (20%) and trisomy of CMYC in 12 out of 55 pts (22%). The following strong correlations among the genetic changes have been seen: six out of seven pts with P53 deletion also showed deletion in chromosome band 13q14 (86%), which was also found in nine out of eleven pts with t(4;14) (82% del 13) and nine out of twelve pts with CMYC trisomy (75% del 13). The estimated event-free (EFS) and overall survival (OS) at four years for the entire study population was 48% and 57%, respectively. No significant difference of the estimated event-free survival at 3 years was seen for pts with del 13 (42% vs 54%, p=0,4), with P53 deletion (43% vs 49%, p=0,27) and for pts with t(4;14) (46% vs 62%, p=0,69) or CMYC overrepresentation (37% vs 50%, p=0,35). Comparison of pts showing both del 13 and P53 deletion, del 13 and t(4;14), del 13 and trisomy of CMYC or t(4;14) and CMYC trisomy with the rest of the study population did not show a significantly reduced EFS either. Even the comparison of pts with any chromosomal abnormalities and pts without any genetic changes detected by FISH did not show a significant difference in EFS (48% vs 50%, p=0,8). These preliminary data suggest that the negative prognostic impact of chromosomal abnormalities such as deletion of 13q14, P53 deletion, t(4;14) and overrepresentation of CMYC may be overcome by allogeneic SCT probably due to the graft versus myeloma effect.