Immunohistochemistry for identification of CCND1 NSD2 and MAF gene rearrangements in plasma cell myeloma

摘要

The t(11;14)/CCND1‐IGH, t(4;14)/NSD2(MMSET)‐IGH, and t(14;16)/IGH‐MAF gene rearrangements detected by fluorescence in situ hybridization (FISH) are used for risk stratification in patients with multiple myeloma (MM). Compared with conventional FISH techniques using fresh cells, immunohistochemistry (IHC) is much more cost‐ and time‐efficient, and can be readily applied to routinely prepared formalin‐fixed, paraffin‐embedded (FFPE) materials. In this study, we performed tissue FISH and IHC employing FFPE specimens, and examined the usefulness of IHC as a tool for detecting style="fixed-case">CCND1, style="fixed-case">NSD2, and style="fixed-case">MAF gene rearrangements. style="fixed-case">CD138 signals were used to identify plasma cells in tissue style="fixed-case">FISH and style="fixed-case">IHC analyses. With cohort 1 (n = 70), we performed tissue style="fixed-case">FISH and subsequently style="fixed-case">IHC, and determined style="fixed-case">IHC cut‐off points. In this cohort, the sensitivity and specificity for the 3 molecules were ≥.90 and ≥.96, respectively. With cohort 2, using style="fixed-case">MM cases with an unknown gene status (n = 120), we performed style="fixed-case">IHC, and the gene status was estimated using the cut‐off points determined with cohort 1. The subsequent style="fixed-case">FISH analysis showed that the sensitivity and specificity for the 3 molecules were ≥.92 and ≥.98, respectively. style="fixed-case">CCND1, style="fixed-case">NSD2, and style="fixed-case">MAF gene rearrangements were estimated accurately by style="fixed-case">IHC, suggesting that conventional style="fixed-case">FISH assays can be replaced by style="fixed-case">IHC.