Project description:The secondary genetic events associated with follicular lymphoma (FL) progression are not well defined. We applied genome-wide BAC array comparative genomic hybridization to 106 diagnostic biopsies of FL to characterize regional genomic imbalances. Using an analytical approach that defined regions of copy number change as intersections between visual annotations and a Hidden Markov model-based algorithm, we identified 71 regional alterations that were recurrent in â?¥10% of cases. These ranged in size from ~200 kb to 44 Mb, affecting chromosomes 1, 5, 6, 7, 8, 10, 12, 17, 18, 19, and 22. We also demonstrated by cluster analysis that 46.2% of the 106 cases could be sub-grouped based on the presence of +1q, +6p/6q-, +7 or +18. Survival analysis showed that 21 of the 71 regions correlated significantly with inferior overall survival (OS). Of these 21 regions, 16 were independent predictors of OS using a multivariate Cox model that included the International Prognostic Index (IPI) Score. Two of these 16 regions (1p36.22-p36.33 and 6q21-q24.3) were also predictors of transformation risk and independent of IPI. These prognostic features may be useful to identify high-risk patients as candidates for risk-adapted therapies. Array comparative genomic hybridization analysis of 106 follicular lymphoma diagnostic biopsies
Project description:Nodal marginal zone lymphoma is a poorly defined entity in the WHO classification, largely based on criteria by exclusion and the diagnosis often remains subjective. Follicular Lymphoma lacking t(14;18), have similar characteristics which results in a major potential diagnostic overlap which this study aims to dissect. Four subgroups of lymphoma samples (n=56) were analyzed with high-resolution arrayCGH; Nodal marginal zone lymphoma, t(14;18)-negative Follicular Lymphoma, localized t(14:18)-positive Follicular Lymphoma and disseminated t(14;18)-positive Follicular Lymphoma. Gains on chromosomes 7, 8 and 12 were observed in all subgroups. The mean number of aberrations was higher in disseminated t(14;18)-positive Follicular Lymphoma compared to localized t(14:18)-positive Follicular Lymphoma (p<0.01) and the majority of alterations in localized t(14:18)-positive Follicular Lymphoma were also found in disseminated t(14;18)-positive Follicular Lymphoma. Nodal marginal zone lymphoma was marked by 3q gains with amplifications of four genes. A different overall pattern of aberrations was seen in t(14;18)-negative Follicular Lymphoma compared to t(14;18)-positive Follicular Lymphoma. t(14;18)-negative Follicular Lymphoma is marked by specific (focal) gains on chromosome 3 as observed in Nodal marginal zone lymphoma. Our results support the notion that localized t(14:18)-positive Follicular Lymphoma represents an early phase of disseminated t(14;18)-positive Follicular Lymphoma. t(14;18)-negative Follicular Lymphoma bears aberrations that are more alike Nodal marginal zone lymphoma, suggesting a relation between these groups.
Project description:Clonal heterogeneity in lymphoid malignancies has been recently reported in adult T-Cell lymphoma/leukemia, peripheral T-cell lymphoma, not otherwise specified, and mantle cell lymphoma (MCL). Our analysis was extended to other types of lymphoma including marginal zone lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma (DLBCL). We examined the results of array comparative genomic hybridization analysis for 332 cases to determine if clonal heterogeneity existed in each case. Results showed that frequencies of clonal heterogeneity varied from 25% to 69% among different types of lymphoma. Multivariate analysis indicated that MCL and DLBCL with clonal heterogeneity showed a significantly poorer prognosis. Interestingly, 9p21.3 (CDKN2A/ 2B) loss and 17p13 (TP53, ATP1B2, SAT2, SHBG) loss were common regions among various types of lymphoma with clonal heterogeneity, suggesting at least in part that loss of these genes may play a role in clonal heterogeneity.
Project description:We studied 277 lymphoma samples (198 FL and 79 transformed FL [tFL]) using a single-nucleotide polymorphism array to identify the secondary chromosomal abnormalities that drive the development of FL and its transformation to diffuse large B-cell lymphoma. Affymetrix 250K NspI SNP arrays were performed according to the manufacturer's directions on DNA extracted from frozen follicular lymphoma or transformed follicular lymphoma tumor specimens
Project description: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.
Project description:Clonal heterogeneity in lymphoid malignancies has been recently reported in adult T-Cell lymphoma/leukemia, peripheral T-cell lymphoma, not otherwise specified, and mantle cell lymphoma (MCL). Our analysis was extended to other types of lymphoma including marginal zone lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma (DLBCL). We examined the results of array comparative genomic hybridization analysis for 332 cases to determine if clonal heterogeneity existed in each case. Results showed that frequencies of clonal heterogeneity varied from 25% to 69% among different types of lymphoma. Multivariate analysis indicated that MCL and DLBCL with clonal heterogeneity showed a significantly poorer prognosis. Interestingly, 9p21.3 (CDKN2A/ 2B) loss and 17p13 (TP53, ATP1B2, SAT2, SHBG) loss were common regions among various types of lymphoma with clonal heterogeneity, suggesting at least in part that loss of these genes may play a role in clonal heterogeneity. We analyzed previously untreated 332 cases of lymphoma (comprising 29 cases of mantle cell lymphoma, 117 cases of diffuse large B-cell lymphoma (DLBCL), 79 cases of Follicular lymphoma, 24 cases of Burkitt lymphoma, 31 cases of mucosa-associated lymphoid tissue (MALT) lymphoma, and 51 peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS)).
Project description:Nodal marginal zone lymphoma is a poorly defined entity in the WHO classification, largely based on criteria by exclusion and the diagnosis often remains subjective. Follicular Lymphoma lacking t(14;18), have similar characteristics which results in a major potential diagnostic overlap which this study aims to dissect. Four subgroups of lymphoma samples (n=56) were analyzed with high-resolution arrayCGH; Nodal marginal zone lymphoma, t(14;18)-negative Follicular Lymphoma, localized t(14:18)-positive Follicular Lymphoma and disseminated t(14;18)-positive Follicular Lymphoma. Gains on chromosomes 7, 8 and 12 were observed in all subgroups. The mean number of aberrations was higher in disseminated t(14;18)-positive Follicular Lymphoma compared to localized t(14:18)-positive Follicular Lymphoma (p<0.01) and the majority of alterations in localized t(14:18)-positive Follicular Lymphoma were also found in disseminated t(14;18)-positive Follicular Lymphoma. Nodal marginal zone lymphoma was marked by 3q gains with amplifications of four genes. A different overall pattern of aberrations was seen in t(14;18)-negative Follicular Lymphoma compared to t(14;18)-positive Follicular Lymphoma. t(14;18)-negative Follicular Lymphoma is marked by specific (focal) gains on chromosome 3 as observed in Nodal marginal zone lymphoma. Our results support the notion that localized t(14:18)-positive Follicular Lymphoma represents an early phase of disseminated t(14;18)-positive Follicular Lymphoma. t(14;18)-negative Follicular Lymphoma bears aberrations that are more alike Nodal marginal zone lymphoma, suggesting a relation between these groups. Four subgroups of follicular lymphoma were analyzed: NMZL (n=14), t-FL (n=12), LOC t+FL (n=16), DIS t+FL (n=14).