Detection of MYD88 L265P in patients with lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia and other B-cell non-Hodgkin lymphomas

BACKGROUND: Recent studies have identified a high prevalence of the MYD88 L265P mutation in lymphoplasmacytic lymphoma (LPL)/Waldenstrom macroglobulinemia (WM) cases, whereas low frequencies have been observed in other B cell non-Hodgkin lymphomas (NHLs). METHODS: We evaluated the sensitivity of the mutant enrichment 3'-modified oligonucleotide (MEMO)-PCR technique, a new detection method. We examined the MYD88 L265P mutation in a series of Korean patients with LPL/WM and other B cell NHLs in bone marrow aspirates, using the MEMO-PCR technique. RESULTS: The sensitivity of MEMO-PCR was estimated to be approximately 10-16.7%. MYD88 L265P was detected in 21 of 28 LPL cases (75%) and only three of 69 B cell NHL cases (4.3%). CONCLUSION: Although MEMO-PCR had relatively low sensitivity, we confirmed the high prevalence of the MYD88 L265P mutation in Korean LPL patients. Our study suggests the diagnostic value of MYD88 L265P for differentiating B-cell NHLs.

Identification of a Rare 3 bp BRAF Gene Deletion in a Thyroid Nodule by Mutant Enrichment with 3'-Modified Oligonucleotides Polymerase Chain Reaction

Papillary thyroid carcinoma (PTC) is the most common malignant thyroid tumor, and 36-69% of PTC cases are caused by mutations in the BRAF gene. The substitution of a valine for a glutamic acid (V600E) comprises up to 95-100% of BRAF mutations; therefore, most diagnostic methods, including allele-specific PCR and real-time PCR, are designed to detect this mutation. Nevertheless, other mutations can also comprise the genetic background of PTC. Recently, a novel and sensitive technique called mutant enrichment with 3'-modified oligonucleotides (MEMO) PCR has been introduced. When we applied allelespecific PCR and MEMO-PCR for the detection of the BRAF V600E mutation, we found an unusual 3' bp deletion mutation (c.1799_1801delTGA) only when using MEMO-PCR. This deletion results in the introduction of a glutamic acid into the B-Raf activation segment (p.V600_K601delinsE), leading to an elevated basal kinase activity of BRAF. This is the first report of a rare 3 bp BRAF deletion in a PTC patient that could not be detected by allele-specific PCR.