1Department of Laboratory Medicine, Center for Diagnostic Oncology, Hospital and Research Institute, National Cancer Center, Goyang, Korea.
2Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
4Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea.
Recent studies have identified a high prevalence of the
We evaluated the sensitivity of the mutant enrichment 3'-modified oligonucleotide (MEMO)-PCR technique, a new detection method. We examined the
The sensitivity of MEMO-PCR was estimated to be approximately 10-16.7%.
Although MEMO-PCR had relatively low sensitivity, we confirmed the high prevalence of the
Lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia (LPL/WM) is a relatively rare subgroup of non-Hodgkin lymphoma (NHL). Differential diagnosis of LPL/WM from other NHLs is somewhat difficult, especially from marginal zone lymphoma (MZL) or B cell lymphoma with plasmacytic differentiation . Recent studies have reported a high prevalence (80-100%) of the
The detection methods for
From a review of LPL/WL and other B-cell NHL cases diagnosed at the Samsung Medical Center between 2001 and 2014, we selected 97 cases with bone marrow involvement, including 28 LPL/WL and 69 other B-cell NHL cases. Patient demographics, clinical features, treatment histories, and hematologic, immunophenotypic, and cytogenetic findings were all comprehensively analyzed. To identify the deletion of 6q, we additionally performed fluorescence in situ hybridization (FISH) using the XL 6q21/6q23 probe (Metasystem, Altlussheim, Germany). For the evaluation of MEMO-PCR, samples were diluted with equimolar normal DNA to produce 1:1, 1:3, 1:5, 1:9, 1:17, 1:21, and 1:41 ratios of mutant DNA.
DNA was extracted from bone marrow aspirate slides using the QIAamp DNA Blood Mini Kit (Qiagen, Foster City, CA, USA) after treating with proteinase K. To detect the
Statistical analysis was performed using PASW Statistics 20.0 software (IBM, Armonk, New York, USA). To compare the clinical parameters between
Patient demographics and clinical characteristics of cases are summarized in Table 1. The mean age was 65 years and the male/female ratio was 1.8:1. Patients generally had mild anemia (mean 9.7 g/dL) with variable white blood cell and platelet counts. All patients had IgM-type monoclonal gammopathies, except for one patient with IgG-type. Chromosomal aberration was detected in three of 25 patients analyzed (12%), including two complex karyotypes and one single balanced translocation. By FISH analysis, a 6q deletion was detected in 38.5% (5/13) of LPL/WM cases, suggesting that the deletion is cryptic. One case was CD5-positive (1/19, 5.3%). The positivity rate of CD23, CD25, and FMC-7 was 29.4% (5/17), 22.2% (2/9), and 50% (9/18), respectively.
Demographic and clinical characteristics of the enrolled patients are summarized in Table 1. The mean age was 56 years and male/female ratio was 3.6:1. Patients generally had mild anemia (mean 11.8 g/dL) with variable white blood cell and platelet counts. Eleven patients had monoclonal gammopathies, which were most commonly of the IgM-type. Chromosome aberration was detected in 36 patients (52.2%).
Using diluted samples, the sensitivity of MEMO-PCR was estimated to be approximately 10–16.7% (Fig. 2). By MEMO-PCR and sequencing of bone marrow aspirate specimens,
None of the clinical and cytogenetic parameters were significantly different between
We observed a high prevalence of the
Several studies have shown the association of the
For molecular testing, we used bone marrow aspirate slides instead of biopsy specimens from primary sites such as lymph nodes. Given that the detection method is sensitive, obtaining samples from bone marrow or peripheral blood specimens will be more practical and easier than performing biopsies on primary sites. One popular method for this purpose is AS-PCR, used in many studies for
Several limitations were encountered in this study. We did not perform extensive clinical and morphologic review of selected cases to differentiate LPL/WM from other lymphoma diagnoses. In addition, only a few cases of MZL or B cell lymphoma with plasmatic differentiation were enrolled in this study. The sensitivity of MEMO-PCR was insufficient to detect minimal mutant levels of
In conclusion, we observed a high prevalence of
Principles of MEMO-PCR for
Sensitivity of MEMO-PCR (estimated to be approximately 10–16.7%) and sequencing analysis.