We identified the genomic signature of ocular adnexal lymphoproliferative disorders (LPDs), especially ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma, IgG4-related ophthalmic disease (IgG4-ROD), reactive lymphoid hyperplasia (RLH), and diffuse large B-cell lymphoma (DLBCL).
We included 52 subjects with ocular adnexal LPDs (13 orbital MALT lymphomas, 16 conjunctival MALT lymphomas, 13 IgG4-RODs, 4 RLHs, and 6 DLBCLs) who had been treated at the Tokyo Medical University Hospital from 2008 to 2012. Genomic DNA was extracted from the tumor tissues and subjected to high-resolution single nucleotide polymorphism array (SNP-A) karyotyping using GeneChip Human Mapping 250K SNP arrays. The array data were investigated using Copy Number Analysis for GeneChips (CNAG) software.
In ocular adnexal MALT lymphomas, the most frequent copy number (CN) gain region was trisomy 3 detected in 31% (9/29), followed by trisomy 18 in 17% (5/29), and 6p and 21q in 14% (4/29). The most frequent CN loss regions were 6q and 9p, detected in 7% (2/29). Uniparental disomy was detected on 6q in 14% (4/29), followed by 3q in 10% (3/29). Copy number variations (CNVs) were not detected in IgG4-RODs and RLHs. Conversely, CNVs were more frequent in DLBCLs than in ocular adnexal MALT lymphomas. Copy number variations were detected in 77% (10/13) of orbital MALT lymphomas and in 67% (11/16) of conjunctival MALT lymphomas.
High-resolution single nucleotide polymorphism array is a useful method for discriminating ocular adnexal lymphomas from benign LPDs. The differences in the chromosomal abnormality patterns may reflect the activity of ocular adnexal LPDs.