MYD88 L265P mutations are correlated with 6q deletion in korean patients with Waldenström macroglobulinemia.

[waldenström macroglobulinemia]

Waldenström macroglobulinemia (WM ) is a malignant lymphoplasma-proliferative disorder with IgM monoclonal gammopathy . A recent whole-genome study identified MYD 88 L 265 P as the key mutation in WM . We investigated MYD 88 mutations in conjunction with cytogenetic study in 22 consecutive Korean WM patients . Conventional G-banding and interphase fluorescence in situ hybridization (FISH ) were performed at regions including 6 q 21 using bone marrow (BM ) aspirates . Sixteen patients were subjected to Sanger sequencing-based MYD 88 mutation study . Five patients (28 %) showed cytogenetic aberrations in G-banding . The incidence of 6 q 21 deletion was 17 % by conventional G-banding and 37 % by FISH . Ten patients (45 %) showed cytogenetic aberrations using FISH : 6 q deletion in eight (37 %) and IGH rearrangement in four (18 %). Two patients had both the 6 q deletion and IGH rearrangement , and two had only the IGH rearrangement . Eleven patients (69 %) presented with the MYD 88 L 265 P mutation . MYD 88 mutations were significantly associated with the presence of 6 q deletions (P = 0 .037 ). Six patients with the 6 q deletion for whom sequencing was possible were found to harbor MYD 88 mutations . The MYD 88 L 265 P mutation was also associated with increased lymphocyte burden in BM biopsy . This is the first report of high frequency MYD 88 L 265 P mutations in Korean WM patients .