Genome-wide DNA methylation analysis along the progression of gastric marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type.

Extra-nodal marginal zone B-cell lymphoma (MZBL) of mucosa-associated lymphoid tissue is an indolent lymphoma mostly affecting the gastrointestinal tract. The lymphoma initially has small-cell morphology (SC-MZBL) and often arises in the background of Helicobacter pylori-induced gastritis. In some cases, a clonal malignant progression to large-cell morphology (LC-MZBL) is observed. Here, we studied the DNA methylation profile of 30 gastric MZBLs along their progression. Genome-wide DNA methylation profiling, identified 7698 significantly differentially methylated loci during gastric MZBL progression (σ/σ ≥0·4, q ≤ 0·001). LC-MZBL showed hypermethylation in comparison to SC-MZBL with an enrichment of regions involved in transcriptional regulation. In conclusion, our present data show that the morphological distinction between SC- and LC-MZBL is reflected by characteristic DNA methylation profiles.