Project description:Melanoma recurrence frequently occurs after a latency period of several years. In vivo studies demonstrated that tumor cells overcoming latency show a T cell-edited phenotype, suggesting a relevant role for CD8+ T cells in maintaining metastatic latency. Here, in a patient model of multiple recurrent lesions, we illustrate the genetic evolution of poorly immunogenic melanoma phenotypes, evolving in the presence of autologous tumor antigen-specific CD8+ T cells. Melanoma cells from two of three late recurrent metastases, developing within a 6-year latency period, lacked HLA class I expression. HLA class I-negative tumor cells became clinically apparent 1.5 and 6 years into stage IV disease. Genome profiling by SNP arrays revealed total T-cell resistance in both metastases originating from a shared chromosome 15q alteration and independently acquired focal B2M gene deletions. A third HLA class I-positive lesion developed in year 3 of stage IV disease. By HLA haplotype loss lesion-derived melanoma cells acquired resistance towards dominant T-cell clonotypes targeting early stage III tumor cells. Early disease melanoma cells showed a dedifferentiated MITFnegative phenotype, recently described to be associated with immunosuppression, in contrast to the MITFhigh phenotype of T cell-edited tumor cells from late metastases. In summary, our study demonstrates that tumor recurrences after long-term latency develop towards T-cell resistance by independent genetic events, suggesting a mechanism of T cell-driven genetic evolution of melanoma as a means to evade immune recognition and tumor immunotherapy. Genetic alterations lead to loss of tumor antigen presentation.
Project description:Melanoma recurrence frequently occurs after a latency period of several years. In vivo studies demonstrated that tumor cells overcoming latency show a T cell-edited phenotype, suggesting a relevant role for CD8+ T cells in maintaining metastatic latency. Here, in a patient model of multiple recurrent lesions, we illustrate the genetic evolution of poorly immunogenic melanoma phenotypes, evolving in the presence of autologous tumor antigen-specific CD8+ T cells. Melanoma cells from two of three late recurrent metastases, developing within a 6-year latency period, lacked HLA class I expression. HLA class I-negative tumor cells became clinically apparent 1.5 and 6 years into stage IV disease. Genome profiling by SNP arrays revealed total T-cell resistance in both metastases originating from a shared chromosome 15q alteration and independently acquired focal B2M gene deletions. A third HLA class I-positive lesion developed in year 3 of stage IV disease. By HLA haplotype loss lesion-derived melanoma cells acquired resistance towards dominant T-cell clonotypes targeting early stage III tumor cells. Early disease melanoma cells showed a dedifferentiated MITFnegative phenotype, recently described to be associated with immunosuppression, in contrast to the MITFhigh phenotype of T cell-edited tumor cells from late metastases. In summary, our study demonstrates that tumor recurrences after long-term latency develop towards T-cell resistance by independent genetic events, suggesting a mechanism of T cell-driven genetic evolution of melanoma as a means to evade immune recognition and tumor immunotherapy. Genetic alterations lead to loss of tumor antigen presentation. Cell lines were generated from tumor material, differences in T cell recognition were observed and Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from the cell lines. SNP analysis of different melanoma cell lines obtained from one melanoma patient (4 cell lines from different metastasis of one patient with matching germline DNA).
Project description:Here we report on a bulk culture termed MCM1, which was derived from a 61 year old male diagnosed with a nodular melanoma stage T2a, N0. At passage three of culturing, DNA was isolated and Affymetrix SNP6.0 array hybridizations were performed. Cultured MCM1 cells revealed overall identical copy number gains and losses as compared with the primary patient-derived lesion and were therefore used in this study.
Project description:Marginal zone B-cell lymphomas (MZL) have been divided into three distinct subtypes (extranodal MZL of MALT type, nodal MZL; splenic MZL). Nevertheless, the relationship between them is still unclear. We performed a comprehensive analysis of genomic DNA copy number changes in a very large series of MZL cases with the aim of addressing this question. Samples from 218 MZL patients (25 nodal, 57 MALT, 134 splenic and two not better specified MZL) were analyzed with the Affymetrix Human Mapping 250K SNP arrays, and the data combined with matched gene expression in 33/218 cases. MALT lymphoma presented significantly more frequently gains at 3p, 6p, 18p and del(6q23) (TNFAIP3/A20), whilst splenic MZL was associated with del(7q31), del(8p). Nodal MZL did not show statistically significant differences when compared with MALT lymphoma while lacked the splenic MZL-related 7q losses. Gains of 3q and 18q gains were common to all three subtypes. Del(8p) was often present together with del(17p) (TP53). While del(17p) did not determine a worse outcome and del(8p) was only of borderline significance, the presence of both deletions had a highly significant negative impact on the outcome of splenic MZL.
Project description:Here we report on a bulk culture termed MCM1, which was derived from a 61 year old male diagnosed with a nodular melanoma stage T2a, N0. At passage three of culturing, DNA was isolated and Affymetrix SNP6.0 array hybridizations were performed. Cultured MCM1 cells revealed overall identical copy number gains and losses as compared with the primary patient-derived lesion and were therefore used in this study. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA, which was extracted from a patient derived melanoma sample and from a cellline generated from the same melanoma sample at passage three.
Project description:Comparison between the copy number of differentially methylated sites between lymph node metastasis from melanoma patients with good prognosis and melanoma brain metastasis. All samples are taken from different patients, and were established as cell lines in the John Wayne Cancer Institute.
Project description:A consanguineous family segregating anhidrosis (recessive, familial) Shared homozygous regions were identified by comparing SNP genotyping results from four affected family members
Project description:Marginal zone B-cell lymphomas (MZL) have been divided into three distinct subtypes (extranodal MZL of MALT type, nodal MZL; splenic MZL). Nevertheless, the relationship between them is still unclear. We performed a comprehensive analysis of genomic DNA copy number changes in a very large series of MZL cases with the aim of addressing this question. Samples from 218 MZL patients (25 nodal, 57 MALT, 134 splenic and two not better specified MZL) were analyzed with the Affymetrix Human Mapping 250K SNP arrays, and the data combined with matched gene expression in 33/218 cases. MALT lymphoma presented significantly more frequently gains at 3p, 6p, 18p and del(6q23) (TNFAIP3/A20), whilst splenic MZL was associated with del(7q31), del(8p). Nodal MZL did not show statistically significant differences when compared with MALT lymphoma while lacked the splenic MZL-related 7q losses. Gains of 3q and 18q gains were common to all three subtypes. Del(8p) was often present together with del(17p) (TP53). While del(17p) did not determine a worse outcome and del(8p) was only of borderline significance, the presence of both deletions had a highly significant negative impact on the outcome of splenic MZL. Copy number analysis of Affymetrix 250K Nsp SNP arrays was performed for a total of 218 MZL samples were analyzed by high resolution genome wide-DNA profiling: 57 MALT lymphoma, 134 splenic MZL, 25 nodal MZL and two MZL where allocation to a specific category was not possible.