Affymetrix SNP array data for follicular lymphoma (FL) and transformed follicular lymphoma (tFL) samples

Follicular lymphoma is the most common indolent non-Hodgkin's lymphoma involving germinal centre B cells, with a subset of patients undergoing transformation to a diffuse large B-cell lymphoma (DLBCL) morphology for which the clinical outcomes are poor. To elucidate the differences in copy number profiles between FL and tFL groups, we performed Affymetrix SNP 6.0 Array analysis on 31 paired FL-tFL cases. We wanted to identify and compare recurrent somatic copy number alterations (CNAs) between the two groups (FL vs. tFL). In addition, the concordance and discordance in the copy neutral loss of heterozygosity (cnLOH) between the two groups were also investigated to identify recurrent target gene regions. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from follicular lymphoma (FL), transformed follicular lymphoma (tFL) and matching germline (GL) sample (if available). Copy number analysis of Affymetrix SNP 6.0 Array were performed on 91 DNA samples, consisting of 31 patients. Among the 31 patients, 19 had matching germline samples, while 12 had no germline samples. The Log R Ratio (LRR) values and the B Allele Frequency (BAF) values were subsequently calculated to search for copy number aberrations and copy neutral (CN)-LOH in the FL and tFL samples. Paired and unpaired analyses were performed accordingly.