Improved clonality detection in Hodgkin lymphoma using the BIOMED-2-based heavy and kappa chain assay: A paraffin-embedded tissue study

摘要

Aims: Although BIOMED-2 polymerase chain reaction (PCR) standardization protocols allow clonality detection in nearly 100% of non-Hodgkin B cell lymphomas, they have not been widely validated for Hodgkin lymphoma (HL). Our aim was to assess BIOMED-2 protocol sensitivity when using non-microdissected, formalin-fixed, paraffin-embedded (FFPE) tissue from HL cases. Methods and results: We studied 69 consecutive HL cases, of which 61 corresponded to classic HL (cHL) and eight to nodular lymphocyte-predominant HL (NLPHL). CD30-positive cell numbers (<10, 10-25 or >25 per ×200 field), background CD20-positive cell density (low or high) and tumour cell immunophenotype were evaluated. IGH and IGK clonality was assessed on FFPE tissue following BIOMED-2 protocols. Of the 58 assessable cHL cases, 15 (25.9%) exhibited IGH and/or IGK clonality; IGH clonality was shown by nine (15.5%) and IGK clonality by 12 (20.7%). Clonality detection rates in cHL improved as CD30-positive Reed-Sternberg (RS) cell density increased and CD20-positive B cell density decreased, although these correlations did not reach statistical significance. Of the eight NLPHL cases studied, none showed clonal rearrangement. Conclusions: Combined study of IGH and IGK rearrangement according to BIOMED-2 protocols improves clonality detection rate (up to 25% of cases) in HL, even when working on non-microdissected FFPE tissue.