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073 Characteristics of DFSP tumors in adenosine deaminase deficient-severe combined immunodeficiency (ADA-SCID)
Carcinogenesis & Cancer Genetics | ABSTRACTS 068
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Stat1-dependent senescence is necessary for cancer control during immunotherapy E Brenner1, B Scho¨rg2, T Wieder1, H Braumu¨ller1, M Kneilling2, J Bauer1, K Ghoreschi1, A Yazdi1 and M Ro¨cken1 1 Dermatology, Eberhard Karls University, Tu¨bingen, Germany and 2 Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tu¨bingen, Germany Cancer immunotherapies with monoclonal antibodies (mAb) against exhaustion-associated surface molecules, known as immune-checkpoints, reactivate T cells cytotoxic for cancers, and significantly improve survival of patients with various types of cancer. These immunecheckpoint inhibitors are directed against cytotoxic T lymphocyte antigen 4 (CTLA-4), programmed death 1 (PD-1) or programmed death ligand 1 (PD-L1), and disruption of their interactions improves the intermediate-term prognosis even in patients with advanced stage IV melanoma. As the immune system is able to kill tumor cells, it is not astonishing that cancer cell killing has also been demonstrated during immune checkpoint inhibitor therapies. Preclinical data, however, has shown that anti-cancer immunity is not limited to killing cancer cells, and other mechanisms, such as permanent growth arrest or cellular senescence may play an important role as well. Here, we first show that treatment of humans with immune-checkpoint inhibitors induced, besides killing, interferon-dominated type I immunity and senescence in regressing melanoma metastases. To investigate the underlying mechanisms in more detail, we analyzed immune checkpoint inhibitors in advanced solid cancers of RIP1-Tag2 mice, expressing large T antigen (Tag) under the insulin promoter. Besides partial killing of tumor cells, therapy with immune-checkpoint inhibitors induced type I immunity, a p16INK4a+/Ki67- senescent phenotype in the remaining cancer cells, and restored long-term survival. In clear contrast, cancers of RIP1-Tag2xSTAT1-/- mice, deficient in interferon-gsignaling, were resistant to interferon-induced senescence, both in vitro and in vivo. As a consequence, therapy of STAT1-deficient cancers with immune-checkpoint inhibitors in RIP1-Tag2xSTAT1-/- mice completely failed. Thus, cancer control by immunotherapy with immune-checkpoint inhibitors strictly requires Stat1-dependent cancer cell senescence.
Genome-wide association study identifies 14 novel risk alleles associated with basal cell carcinoma HS Chahal1, W Wu2, K Ransohoff1, L Yang3, H Hedlin3, M Desai3, Y Lin2, H Dai2,4, AA Qureshi5,6,7, W Li5,6, P Kraft8,9, D Hinds10, J Tang1, J Han2,8 and K Sarin1 1 Dermatology, Stanford School of Medicine, Stanford, CA, 2 Epidemiology, Indiana University, Indianapolis, IN, 3 Medicine (Biostatistics), Stanford University, Stanford, CA, 4 Epidemiology and Biostatistics, Tianjin Medical University Cancer Hospital and Institute, Tianjin, China, 5 Dermatology, Brown University, Providence, RI, 6 Epidemiology, Brown University, Providence, RI, 7 Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 8 Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, 9 Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA and 10 23andMe Inc., Mountain View, CA Basal cell carcinoma (BCC) is the most common cancer worldwide and contributes substantially to morbidity. Since 2008, 6 population-based genome-wide association studies (GWAS) of BCC have been reported, identifying 16 regions of susceptibility. To identify additional susceptibility loci, we conducted a two-stage GWAS of 17,187 BCC cases and 287,054 controls, making this the largest BCC GWAS to date. The stage 1 set consisted of 12,945 cases and 274,252 controls from the 23andMe research participant cohort, and stage 2 consisted of 4,242 cases and 12,802 controls from the Nurses’ Health/Health Professionals’ cohort. Meta-analysis of the combined data uncovered 14 novel susceptibility loci for BCC reaching genome-wide significance (P<510e8), and also confirmed 12 previously reported associations. These 14 novel loci, some of which are expression quantitative trait loci or keratinocyte regulatory elements, implicate a diverse set of genes—involved in telomere maintenance, immune regulation, and tumor suppression—in BCC susceptibility. Further investigation of these loci will deepen our understanding of BCC pathogenesis and improve our ability to prevent these common tumors.
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Cyclin D1 promoter -56 and -54 bp CpG un-methylation predicts invasive progression in arsenic-induced Bowen’s disease H Yu1,2, W Liao3, C Chai4 and C Lee5 1 National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan, 2 Department of Dermatology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan, 3 Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan, 4 Department of Pathology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan and 5 Department of Dermatology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan Importance: Patients with arsenic-induced Bowen’s disease (As-BD) are at risk of developing invasive cancers. However, a larger scale longitudinal follow-up study on the association between As-BD and invasive cancers is still lacking. Objective: This study aims to investigate the underlying molecular mechanisms of this malignant progression in the skin and internal organs. Design: We collected specimens from 40 pathologically confirmed As-BD patients and followed up for 5 years. Results: Flow cytometric analysis of skin specimens showed aneuploid (n¼15), G2/M arrest (n¼22), and normal (n¼3) DNA histograms. No patients with normal DNA histograms developed invasive cancers, whereas 13 developed invasive cancers in the aneuploid group and 2 developed invasive cancers in the G2/M arrest group. The aneuploid group showed a high risk of invasive cancer development (Odds ratio¼65.0). In all assessed aneuploid specimens, the Cyclin D1 (CCND1) promoter hypomethylation was observed. Statistically, percentage of un-methylation more than 55.85% among 17 detected CpG sites in CCND1 promoter showed extremely high predictive power in the occurrence of invasive arsenical cancers, with 100% sensitivity and 100% specificity. The un-methylation at -56 and -54 bp CpG sites was statistically significantly associated with invasive arsenical cancer development (p¼1.29 10-5). Conclusions: The results demonstrated that AsBD lesions showing an aneuploid DNA histogram had a high risk of invasive cancer development. Un-methyaltion at -56 and -54 bp CpG in the CCND1 promoter serves as a predictor for invasive progression in As-BD patients.
Novel FISH probe panel for the detection of gene copy number alterations in CTCL J Weed1, J Gibson1, J Lewis1, K Carlson1, F Foss1, J Choi3, P Li2 and M Girardi1 1 Dermatology, Yale School of Medicine, New Haven, CT, 2 Genetics, Yale School of Medicine, New Haven, CT and 3 Dermatology, Feinberg School of Medicine, Chicago, IL To help facilitate the rapid genetic characterization of clonal, malignant blood involvement in patients with cutaneous T cell lymphoma (CTCL), we have developed a panel of fluorescence in situ hybridization (FISH) probes tailored to frequently recurring genetic copy number alterations, designed to detect abnormalities in >95% of patients with CTCL blood involvement. The panel comprises 11 probes: 5 previously available probes (TP53, MYC, ATM, RB, and CDKN2A), and 6 newly developed probes targeting ARID1A, ZEB1, STAT3/5B, DNMT3A, CARD11, and FAS. Samples were processed according to standard protocols for clinical FISH studies: gradient centrifugation of peripheral blood, optional sorting for purification of malignant subpopulations, and overnight FISH staining under standard conditions. The panel of 11 probes detected copy number alterations in flow cytometry or magnetic bead sorted samples in patients with T cell counts as low as 484 cells/mL (normal range 593-2245) as well as in a non-sorted whole blood sample from a patient whose percent abnormal T cells of total white blood cells was in the general detection range (>5%) for FISH (where abnormal T cell populations are typically identified within subset expansions of CD4+CD7-, CD4+CD26-, or CD4+ and V-beta subtype). Marked heterogeneity of FISH results is seen among patient samples, consistent with recently published exome and genome sequencing studies of CTCL. Given the variability of clinical outcomes and the wide spectrum of blood involvement in CTCL subtypes, this panel enables physicians to quickly clarify the extent of key genetic alterations within CD4+ T cell populations in the peripheral blood. Our CTCL FISH panel may be useful in improving diagnostic accuracy for patients with inflammatory dermatoses and abnormal flow cytometry of CD4+ populations, and inform clinical prognosis and response to treatments with mechanisms of action relevant to the represented genes.
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HPV genotypes in genital dysplasia and carcinoma in GATA2 deficiency DC Pichard1, K van Doorslaer2, AA McBride2, CS Zerbe3, P Stratton4, SM Holland3, HH Kong1 and EW Cowen1 1 Dermatology, National Institutes of Health, NCI, Bethesda, MD, 2 Laboratory of Viral Diseases, NIAID, NIH, Bethesda, MD, 3 Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, MD and 4 Office of the Clinical Director, NICHD, NIH, Bethesda, MD Loss of function mutations in GATA2, a zinc-finger transcription factor expressed in hematopoietic stem cells, are responsible for an autosomal dominant primary immunodeficiency (GATA2 deficiency). This heterogeneous multisystem disease is associated with cytopenias (particularly monocytopenia), myelodysplasia/acute myeloid leukemia, peripheral edema, hearing loss, and pulmonary alveolar proteinosis, among other manifestations. Human papillomavirus (HPV) infection occurs in 63% of GATA2 deficiency patients, resulting in dysplasia or squamous cell carcinoma (SCC) of the head and neck or genitalia in 35% of patients with GATA2 deficiency. HPV infection in women often occurs in the second decade of life and results in severe cervical or vulvar dysplasia and carcinoma. Approximately 70% of cervical carcinoma in the general population is due to HPV16 or HPV18; however, the specific HPV genotypes in genital dysplasia and carcinoma in patients with GATA2 deficiency is unknown. In this study, we identified the HPV genotypes in vulvar and cervical dysplasia or carcinoma specimens from nine women with GATA2 deficiency. PCR amplification using degenerate SPF primers was performed on DNA obtained from all tissue samples. HPV16 infection was most common (n¼4) and occurred in two SCC, consistent with the known oncogenic role of this genotype in the general population. In addition, the high-risk HPV types HPV18 (n¼2), HPV33 (n¼1), and HPV56 (n¼1), and probable carcinogenic type HPV66 (n¼2), were also identified. HPV90, which is not considered a high-risk type, was identified in 2 of the 9 dysplastic lesions. Our results suggest that high-risk HPV types are associated with the majority of dysplastic or cancerous genital lesions in women with GATA2 deficiency. Vaccination to prevent acquisition of HPV may mitigate the risk of HPV disease in these women.
Characteristics of DFSP tumors in adenosine deaminase deficient-severe combined immunodeficiency (ADA-SCID) DC Pichard1, PL Haun2, AL Navarro4, D Lopez-Terrada4, I Brownell1, EY Chu2, M Miettinen3 and EW Cowen1 1 Dermatology, NIH, NCI, CCR, Bethesda, MD, 2 Dermatology, University of Pennsylvania, Philadelphia, PA, 3 Laboratory of Pathology, NIH, NCI, CCR, Bethesda, MD and 4 Pathology, Texas Children’s Hospital, Houston, TX Dermatofibrosarcoma protuberans (DFSP) is a slow growing, locally invasive soft tissue sarcoma that typically develops on the trunk and proximal extremities of young adults. The tumor is classically nodular in appearance and histology displays a dermal CD34 spindle cell tumor. Diagnosis is supported by the presence of a translocation between chromosomes 17 and 22, resulting in a COL1A1-PDGFB fusion gene. We evaluated 10 children with ADASCID with DFSP tumors carrying the COL1A1-PDGFB fusion transcripts. The tumors were atypical in multiple ways: early age of onset, clinical appearance of subtle, flat indurated, plaques, and nondiagnostic histologic features. Additionally, 4 patients had multiple discrete DFSP tumors, which is highly unusual for this sarcoma. To better understand the nature of DFSP tumors associated with ADA-SCID, we compared the histologic findings of 16 ADASCID-associated DFSP tumors to 14 DFSP tumors from children without ADA-SCID. The majority of the ADA-SCID DFSP tumors demonstrated low cellularity and lacked the classical storiform pattern, but all stained intensely for CD34. Fibrosarcomatous changes were not seen in the ADA-SCID associated DFSP tumors. RT-PCR was performed on RNA extracted from 11 tumors in 8 ADA-SCID patients. Analysis of cDNA sequence was performed using BLASTn. Consistent with previous reports, the t(17;22) translocation produced fusion transcripts with splice events between variable a helical coding exons in COL1A1 and exon 2 in PDGFB. Interestingly, multicentric tumors from individual patients in our cohort did not demonstrate molecular clonality, suggesting independent synchronous origins. Collectively our data suggest that patients with the primary immunodeficiency ADA-SCID have an increased propensity to develop one or more independent DFSP tumors that are clinically and histologically atypical.
www.jidonline.org S13
069
Stat1-dependent senescence is necessary for cancer control during immunotherapy E Brenner1, B Scho¨rg2, T Wieder1, H Braumu¨ller1, M Kneilling2, J Bauer1, K Ghoreschi1, A Yazdi1 and M Ro¨cken1 1 Dermatology, Eberhard Karls University, Tu¨bingen, Germany and 2 Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tu¨bingen, Germany Cancer immunotherapies with monoclonal antibodies (mAb) against exhaustion-associated surface molecules, known as immune-checkpoints, reactivate T cells cytotoxic for cancers, and significantly improve survival of patients with various types of cancer. These immunecheckpoint inhibitors are directed against cytotoxic T lymphocyte antigen 4 (CTLA-4), programmed death 1 (PD-1) or programmed death ligand 1 (PD-L1), and disruption of their interactions improves the intermediate-term prognosis even in patients with advanced stage IV melanoma. As the immune system is able to kill tumor cells, it is not astonishing that cancer cell killing has also been demonstrated during immune checkpoint inhibitor therapies. Preclinical data, however, has shown that anti-cancer immunity is not limited to killing cancer cells, and other mechanisms, such as permanent growth arrest or cellular senescence may play an important role as well. Here, we first show that treatment of humans with immune-checkpoint inhibitors induced, besides killing, interferon-dominated type I immunity and senescence in regressing melanoma metastases. To investigate the underlying mechanisms in more detail, we analyzed immune checkpoint inhibitors in advanced solid cancers of RIP1-Tag2 mice, expressing large T antigen (Tag) under the insulin promoter. Besides partial killing of tumor cells, therapy with immune-checkpoint inhibitors induced type I immunity, a p16INK4a+/Ki67- senescent phenotype in the remaining cancer cells, and restored long-term survival. In clear contrast, cancers of RIP1-Tag2xSTAT1-/- mice, deficient in interferon-gsignaling, were resistant to interferon-induced senescence, both in vitro and in vivo. As a consequence, therapy of STAT1-deficient cancers with immune-checkpoint inhibitors in RIP1-Tag2xSTAT1-/- mice completely failed. Thus, cancer control by immunotherapy with immune-checkpoint inhibitors strictly requires Stat1-dependent cancer cell senescence.
Genome-wide association study identifies 14 novel risk alleles associated with basal cell carcinoma HS Chahal1, W Wu2, K Ransohoff1, L Yang3, H Hedlin3, M Desai3, Y Lin2, H Dai2,4, AA Qureshi5,6,7, W Li5,6, P Kraft8,9, D Hinds10, J Tang1, J Han2,8 and K Sarin1 1 Dermatology, Stanford School of Medicine, Stanford, CA, 2 Epidemiology, Indiana University, Indianapolis, IN, 3 Medicine (Biostatistics), Stanford University, Stanford, CA, 4 Epidemiology and Biostatistics, Tianjin Medical University Cancer Hospital and Institute, Tianjin, China, 5 Dermatology, Brown University, Providence, RI, 6 Epidemiology, Brown University, Providence, RI, 7 Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 8 Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, 9 Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA and 10 23andMe Inc., Mountain View, CA Basal cell carcinoma (BCC) is the most common cancer worldwide and contributes substantially to morbidity. Since 2008, 6 population-based genome-wide association studies (GWAS) of BCC have been reported, identifying 16 regions of susceptibility. To identify additional susceptibility loci, we conducted a two-stage GWAS of 17,187 BCC cases and 287,054 controls, making this the largest BCC GWAS to date. The stage 1 set consisted of 12,945 cases and 274,252 controls from the 23andMe research participant cohort, and stage 2 consisted of 4,242 cases and 12,802 controls from the Nurses’ Health/Health Professionals’ cohort. Meta-analysis of the combined data uncovered 14 novel susceptibility loci for BCC reaching genome-wide significance (P<510e8), and also confirmed 12 previously reported associations. These 14 novel loci, some of which are expression quantitative trait loci or keratinocyte regulatory elements, implicate a diverse set of genes—involved in telomere maintenance, immune regulation, and tumor suppression—in BCC susceptibility. Further investigation of these loci will deepen our understanding of BCC pathogenesis and improve our ability to prevent these common tumors.
070
071
Cyclin D1 promoter -56 and -54 bp CpG un-methylation predicts invasive progression in arsenic-induced Bowen’s disease H Yu1,2, W Liao3, C Chai4 and C Lee5 1 National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan, 2 Department of Dermatology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan, 3 Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan, 4 Department of Pathology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan and 5 Department of Dermatology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan Importance: Patients with arsenic-induced Bowen’s disease (As-BD) are at risk of developing invasive cancers. However, a larger scale longitudinal follow-up study on the association between As-BD and invasive cancers is still lacking. Objective: This study aims to investigate the underlying molecular mechanisms of this malignant progression in the skin and internal organs. Design: We collected specimens from 40 pathologically confirmed As-BD patients and followed up for 5 years. Results: Flow cytometric analysis of skin specimens showed aneuploid (n¼15), G2/M arrest (n¼22), and normal (n¼3) DNA histograms. No patients with normal DNA histograms developed invasive cancers, whereas 13 developed invasive cancers in the aneuploid group and 2 developed invasive cancers in the G2/M arrest group. The aneuploid group showed a high risk of invasive cancer development (Odds ratio¼65.0). In all assessed aneuploid specimens, the Cyclin D1 (CCND1) promoter hypomethylation was observed. Statistically, percentage of un-methylation more than 55.85% among 17 detected CpG sites in CCND1 promoter showed extremely high predictive power in the occurrence of invasive arsenical cancers, with 100% sensitivity and 100% specificity. The un-methylation at -56 and -54 bp CpG sites was statistically significantly associated with invasive arsenical cancer development (p¼1.29 10-5). Conclusions: The results demonstrated that AsBD lesions showing an aneuploid DNA histogram had a high risk of invasive cancer development. Un-methyaltion at -56 and -54 bp CpG in the CCND1 promoter serves as a predictor for invasive progression in As-BD patients.
Novel FISH probe panel for the detection of gene copy number alterations in CTCL J Weed1, J Gibson1, J Lewis1, K Carlson1, F Foss1, J Choi3, P Li2 and M Girardi1 1 Dermatology, Yale School of Medicine, New Haven, CT, 2 Genetics, Yale School of Medicine, New Haven, CT and 3 Dermatology, Feinberg School of Medicine, Chicago, IL To help facilitate the rapid genetic characterization of clonal, malignant blood involvement in patients with cutaneous T cell lymphoma (CTCL), we have developed a panel of fluorescence in situ hybridization (FISH) probes tailored to frequently recurring genetic copy number alterations, designed to detect abnormalities in >95% of patients with CTCL blood involvement. The panel comprises 11 probes: 5 previously available probes (TP53, MYC, ATM, RB, and CDKN2A), and 6 newly developed probes targeting ARID1A, ZEB1, STAT3/5B, DNMT3A, CARD11, and FAS. Samples were processed according to standard protocols for clinical FISH studies: gradient centrifugation of peripheral blood, optional sorting for purification of malignant subpopulations, and overnight FISH staining under standard conditions. The panel of 11 probes detected copy number alterations in flow cytometry or magnetic bead sorted samples in patients with T cell counts as low as 484 cells/mL (normal range 593-2245) as well as in a non-sorted whole blood sample from a patient whose percent abnormal T cells of total white blood cells was in the general detection range (>5%) for FISH (where abnormal T cell populations are typically identified within subset expansions of CD4+CD7-, CD4+CD26-, or CD4+ and V-beta subtype). Marked heterogeneity of FISH results is seen among patient samples, consistent with recently published exome and genome sequencing studies of CTCL. Given the variability of clinical outcomes and the wide spectrum of blood involvement in CTCL subtypes, this panel enables physicians to quickly clarify the extent of key genetic alterations within CD4+ T cell populations in the peripheral blood. Our CTCL FISH panel may be useful in improving diagnostic accuracy for patients with inflammatory dermatoses and abnormal flow cytometry of CD4+ populations, and inform clinical prognosis and response to treatments with mechanisms of action relevant to the represented genes.
072
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HPV genotypes in genital dysplasia and carcinoma in GATA2 deficiency DC Pichard1, K van Doorslaer2, AA McBride2, CS Zerbe3, P Stratton4, SM Holland3, HH Kong1 and EW Cowen1 1 Dermatology, National Institutes of Health, NCI, Bethesda, MD, 2 Laboratory of Viral Diseases, NIAID, NIH, Bethesda, MD, 3 Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, MD and 4 Office of the Clinical Director, NICHD, NIH, Bethesda, MD Loss of function mutations in GATA2, a zinc-finger transcription factor expressed in hematopoietic stem cells, are responsible for an autosomal dominant primary immunodeficiency (GATA2 deficiency). This heterogeneous multisystem disease is associated with cytopenias (particularly monocytopenia), myelodysplasia/acute myeloid leukemia, peripheral edema, hearing loss, and pulmonary alveolar proteinosis, among other manifestations. Human papillomavirus (HPV) infection occurs in 63% of GATA2 deficiency patients, resulting in dysplasia or squamous cell carcinoma (SCC) of the head and neck or genitalia in 35% of patients with GATA2 deficiency. HPV infection in women often occurs in the second decade of life and results in severe cervical or vulvar dysplasia and carcinoma. Approximately 70% of cervical carcinoma in the general population is due to HPV16 or HPV18; however, the specific HPV genotypes in genital dysplasia and carcinoma in patients with GATA2 deficiency is unknown. In this study, we identified the HPV genotypes in vulvar and cervical dysplasia or carcinoma specimens from nine women with GATA2 deficiency. PCR amplification using degenerate SPF primers was performed on DNA obtained from all tissue samples. HPV16 infection was most common (n¼4) and occurred in two SCC, consistent with the known oncogenic role of this genotype in the general population. In addition, the high-risk HPV types HPV18 (n¼2), HPV33 (n¼1), and HPV56 (n¼1), and probable carcinogenic type HPV66 (n¼2), were also identified. HPV90, which is not considered a high-risk type, was identified in 2 of the 9 dysplastic lesions. Our results suggest that high-risk HPV types are associated with the majority of dysplastic or cancerous genital lesions in women with GATA2 deficiency. Vaccination to prevent acquisition of HPV may mitigate the risk of HPV disease in these women.
Characteristics of DFSP tumors in adenosine deaminase deficient-severe combined immunodeficiency (ADA-SCID) DC Pichard1, PL Haun2, AL Navarro4, D Lopez-Terrada4, I Brownell1, EY Chu2, M Miettinen3 and EW Cowen1 1 Dermatology, NIH, NCI, CCR, Bethesda, MD, 2 Dermatology, University of Pennsylvania, Philadelphia, PA, 3 Laboratory of Pathology, NIH, NCI, CCR, Bethesda, MD and 4 Pathology, Texas Children’s Hospital, Houston, TX Dermatofibrosarcoma protuberans (DFSP) is a slow growing, locally invasive soft tissue sarcoma that typically develops on the trunk and proximal extremities of young adults. The tumor is classically nodular in appearance and histology displays a dermal CD34 spindle cell tumor. Diagnosis is supported by the presence of a translocation between chromosomes 17 and 22, resulting in a COL1A1-PDGFB fusion gene. We evaluated 10 children with ADASCID with DFSP tumors carrying the COL1A1-PDGFB fusion transcripts. The tumors were atypical in multiple ways: early age of onset, clinical appearance of subtle, flat indurated, plaques, and nondiagnostic histologic features. Additionally, 4 patients had multiple discrete DFSP tumors, which is highly unusual for this sarcoma. To better understand the nature of DFSP tumors associated with ADA-SCID, we compared the histologic findings of 16 ADASCID-associated DFSP tumors to 14 DFSP tumors from children without ADA-SCID. The majority of the ADA-SCID DFSP tumors demonstrated low cellularity and lacked the classical storiform pattern, but all stained intensely for CD34. Fibrosarcomatous changes were not seen in the ADA-SCID associated DFSP tumors. RT-PCR was performed on RNA extracted from 11 tumors in 8 ADA-SCID patients. Analysis of cDNA sequence was performed using BLASTn. Consistent with previous reports, the t(17;22) translocation produced fusion transcripts with splice events between variable a helical coding exons in COL1A1 and exon 2 in PDGFB. Interestingly, multicentric tumors from individual patients in our cohort did not demonstrate molecular clonality, suggesting independent synchronous origins. Collectively our data suggest that patients with the primary immunodeficiency ADA-SCID have an increased propensity to develop one or more independent DFSP tumors that are clinically and histologically atypical.
www.jidonline.org S13