RESUMO
Chromosomal region 1p22 is deleted in ⩾20% of multiple myeloma (MM) patients, suggesting the presence of an unidentified tumor suppressor. Using high-resolution genomic profiling, we delimit a 58 kb minimal deleted region (MDR) on 1p22.1 encompassing two genes: ectopic viral integration site 5 (EVI5) and ribosomal protein L5 (RPL5). Low mRNA expression of EVI5 and RPL5 was associated with worse survival in diagnostic cases. Patients with 1p22 deletion had lower mRNA expression of EVI5 and RPL5, however, 1p22 deletion status is a bad predictor of RPL5 expression in some cases, suggesting that other mechanisms downregulate RPL5 expression. Interestingly, RPL5 but not EVI5 mRNA levels were significantly lower in relapsed patients responding to bortezomib and; both in newly diagnosed and relapsed patients, bortezomib treatment could overcome their bad prognosis by raising their progression-free survival to equal that of patients with high RPL5 expression. In conclusion, our genetic data restrict the MDR on 1p22 to EVI5 and RPL5 and although the role of these genes in promoting MM progression remains to be determined, we identify RPL5 mRNA expression as a biomarker for initial response to bortezomib in relapsed patients and subsequent survival benefit after long-term treatment in newly diagnosed and relapsed patients.
Assuntos
Antineoplásicos/uso terapêutico , Bortezomib/uso terapêutico , Deleção Cromossômica , Cromossomos Humanos Par 1 , Mieloma Múltiplo/genética , Proteínas Ribossômicas/genética , Proteínas de Ligação a DNA/genética , Genes Supressores de Tumor , Humanos , Proteína do Locus do Complexo MDS1 e EVI1 , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/mortalidade , Mutação , Proto-Oncogenes/genética , RNA Mensageiro/análise , Fatores de Transcrição/genéticaRESUMO
BAP1 germline mutations predispose to a cancer predisposition syndrome that includes mesothelioma, cutaneous melanoma, uveal melanoma and other cancers. This co-occurrence suggests that these tumors share a common carcinogenic pathway. To evaluate this hypothesis, we studied 40 Italian families with mesothelioma and/or melanoma. The probands were sequenced for BAP1 and for the most common melanoma predisposition genes (i.e. CDKN2A, CDK4, TERT, MITF and POT1) to investigate if these genes may also confer susceptibility to mesothelioma. In two out of six families with both mesothelioma and melanoma we identified either a germline nonsense mutation (c.1153C > T, p.Arg385*) in BAP1 or a recurrent pathogenic germline mutation (c.301G > T, p.Gly101Trp) in CDKN2A. Our study suggests that CDKN2A, in addition to BAP1, could be involved in the melanoma and mesothelioma susceptibility, leading to the rare familial cancer syndromes. It also suggests that these tumors share key steps that drive carcinogenesis and that other genes may be involved in inherited predisposition to malignant mesothelioma and melanoma.
Assuntos
Biomarcadores Tumorais/genética , Códon sem Sentido , Inibidor de Quinase Dependente de Ciclina p18/genética , Mutação em Linhagem Germinativa , Melanoma/genética , Mesotelioma/genética , Neoplasias Cutâneas/genética , Proteínas Supressoras de Tumor/genética , Ubiquitina Tiolesterase/genética , Adolescente , Adulto , Idoso , Biomarcadores Tumorais/análise , Inibidor p16 de Quinase Dependente de Ciclina , Inibidor de Quinase Dependente de Ciclina p18/análise , Análise Mutacional de DNA , Bases de Dados Factuais , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Hereditariedade , Humanos , Imuno-Histoquímica , Itália , Masculino , Melanoma/química , Melanoma/patologia , Mesotelioma/química , Mesotelioma/patologia , Pessoa de Meia-Idade , Linhagem , Fenótipo , Fatores de Risco , Neoplasias Cutâneas/química , Neoplasias Cutâneas/patologia , Proteínas Supressoras de Tumor/análise , Ubiquitina Tiolesterase/análise , Adulto JovemRESUMO
Malignant pleural mesothelioma (MPM) is a rare aggressive tumor associated with asbestos exposure. The possible role of genetic factors has also been suggested and MPM has been associated with single nucleotide polymorphisms (SNPs) of xenobiotic and oxidative metabolism enzymes. We have identified an association of the DNA repair gene XRCC1 with MPM in the population of Casale Monferrato, a town exposed to high asbestos pollution. To extend this observation we examined 35 SNPs in 15 genes that could be involved in MPM carcinogenicity in 220 MPM patients and 296 controls from two case-control studies conducted in Casale (151 patients, 252 controls) and Turin (69 patients, 44 controls), respectively. Unconditional multivariate logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). Two DNA repair genes were associated with MPM, i.e. XRCC1 and ERCC1. Considering asbestos-exposed only, the risk increased with the increasing number of XRCC1-399Q alleles (Casale: OR=1.44, 95%CI 1.02-2.03; Casale+Turin: OR=1.34, 95%CI 0.98-1.84) or XRCC1 -77T alleles (Casale+Turin: OR=1.33, 95%CI 0.97-1.81). The XRCC1-TGGGGGAACAGA haplotype was significantly associated with MPM (Casale: OR=1.76, 95%CI 1.04-2.96). Patients heterozygotes for ERCC1 N118N showed an increased OR in all subjects (OR=1.66, 95%CI 1.06-2.60) and in asbestos-exposed only (OR=1.59, 95%CI 1.01-2.50). When the dominant model was considered (i.e. ERCC1 heterozygotes CT plus homozygotes CC versus homozygotes TT) the risk was statistically significant both in all subjects (OR=1.61, 95%CI 1.06-2.47) and in asbestos-exposed only (OR=1.56, 95%CI 1.02-2.40). The combination of ERCC1 N118N and XRCC1 R399Q was statistically significant (Casale: OR=2.02, 95%CI 1.01-4.05; Casale+Turin: OR=2.39, 95%CI 1.29-4.43). The association of MPM with DNA repair genes support the hypothesis that an increased susceptibility to DNA damage may favour asbestos carcinogenicity.
