Evaluation of cerebrospinal clonal gene rearrangement in newly diagnosed non-Hodgkin's lymphoma patients

Combining MYD88 L265P mutation detection and clonality determination on CSF cellular and cell-free DNA improves diagnosis of primary CNS lymphoma

Diagnosis of primary central nervous system lymphoma (PCNSL) is challenging, and although brain biopsy remains the gold standard, cerebrospinal fluid (CSF) constitutes a less invasive source of lymphomatous biomarkers. In a retrospective cohort of 54 PCNSL cases tested at diagnosis or relapse, we evaluated the contribution of immunoglobulin heavy chain (IGH) gene clonality and MYD88 L265P detection on both CSF cell pellets and supernatants, in comparison with cytology, flow cytometry, interleukin (IL)-10 and IL-6 quantification. Clonality assessment included a new assay to detect partial IGH-DJ rearrangements. Clonal IGH rearrangements and/or MYD88 L265P mutation were detected in 27 (50%) cell pellets and 24 (44%) supernatant cell-free (cf) DNA. Combining analyses on both compartments, 36 (66%) cases had at least one detectable molecular marker, present only in cfDNA for 9 (16%) of them. While cytology and flow cytometry were positive in only 7 (13.0%) and 9 (17.3%) cases respectively, high IL-10 levels were observed in 36 (66.7%) cases. Overall, taking into account molecular and cytokine results, 46/54 (85%) cases had at least one lymphomatous biomarker detectable in the CSF. These results show that this combination of biomarkers evaluated on both cell pellet and supernatant CSF fractions improves significantly the biological diagnosis of PCNSL.

Global, regional and national burden of non-Hodgkin lymphoma from 1990 to 2017: estimates from global burden of disease study in 2017

BACKGROUD

Non-Hodgkin lymphoma (NHL) is a common B/NK/T cell lymphoma. We collected detailed data about the incidence and mortality of NHL from Global Burden of Disease (GBD) Study in 2017 and extensively assessed the disease burden of NHL at the global level and also analysed its current trends according to sex, age, socio-demographic index (SDI), country and region.

METHODS

By obtaining relevant data from Global Burden of Disease Study in 2017, estimated annual percentage changes (EAPCs) of age-standardized rate (ASR) were calculated to assess the current trends of the rate of incidence and mortality.

RESULTS

Globally, ASR of incidence in NHL was increased while ASR of mortality and its annual percentage change was relatively stable. EAPCs in the incidence of NHL decreased in the low SDI regions but increased in the high SDI regions. The ratio of male to female mortalities was the highest in the 50-69-year-old age group, especially in the middle and middle-high SDI regions.

CONCLUSION

The incidence of NHL was increased globally, whereas the deaths and its annual percentage change were relatively stable from 1990 to 2017.Key messagesAge-standardized rate (ASR) of incidence in NHL was increased globally from 1990 to 2017.ASR of mortality and its annual percentage change in NHL were relatively stable globally from 1990 to 2017.Estimated annual percentage changes (EAPCs) in the incidence of NHL decreased in the low socio-demographic index (SDI) regions but increased in the high SDI regions.

Detection of clonotypic DNA in the cerebrospinal fluid as a marker of central nervous system invasion in lymphoma

The NGS-MRD assay detected clonotypic DNA in 100% of CSF samples from patients who had lymphoma with parenchymal CNS involvement.

Clonotypic DNA in CSF was present in 36% of newly diagnosed aggressive lymphomas and was associated with a 29% risk of CNS recurrence.

The diagnosis of parenchymal central nervous system (CNS) invasion and prediction of risk for future CNS recurrence are major challenges in the management of aggressive lymphomas, and accurate biomarkers are needed to supplement clinical risk predictors. For this purpose, we studied the results of a next-generation sequencing (NGS)–based assay that detects tumor-derived DNA for clonotypic immunoglobulin gene rearrangements in the cerebrospinal fluid (CSF) of patients with lymphomas. Used as a diagnostic tool, the NGS-minimal residual disease (NGS-MRD) assay detected clonotypic DNA in 100% of CSF samples from 13 patients with known CNS involvement. They included 7 patients with parenchymal brain disease only, whose CSF tested negative by standard cytology and flow cytometry, and 6 historical DNA aliquots collected from patients at a median of 39 months before accession, which had failed to show clonal rearrangements using standard polymerase chain reaction. For risk prognostication, we prospectively collected CSF from 22 patients with newly diagnosed B-cell lymphomas at high clinical risk of CNS recurrence, of whom 8 (36%) had detectable clonotypic DNA in the CSF. Despite intrathecal prophylaxis, a positive assay of CSF was associated with a 29% cumulative risk of CNS recurrence within 12 months of diagnosis, in contrast with a 0% risk among patients with negative CSF (P = .045). These observations suggest that detection of clonotypic DNA can aid in the diagnosis of suspected parenchymal brain recurrence in aggressive lymphoma. Furthermore, the NGS-MRD assay may enhance clinical risk assessment for CNS recurrence among patients with newly diagnosed lymphomas and help select those who may benefit most from novel approaches to CNS-directed prophylaxis.