RESUMEN
P53 mutation has been reported in various solid tumors, acute leukemia and myelodysplastic syndrome (MDS), but the diagnostic significance of p53 in MDS remains to be determined. The purpose of the present paper was to examine p53 mutation and immunostaining of the same patients, because there have been few reports of simultaneous analysis of these markers. Seven p53 mutations were observed among 37 MDS and 11 cases of overt leukemia transformed from MDS (MDS-OL). Mutated p53 mainly observed in high-risk MDS had more intense p53 staining than in MDS with wild-type p53 overexpression. Aplastic anemia (AA) produced no p53 staining. The percentage of p53 staining in MDS (71%) was higher than that of mutated p53 (11%) but did not reach 100% of MDS cases studied, therefore the authors attempted to differentiate MDS, especially refractory anemia (RA) and AA, using a combination of p53 immunostaining, hemoglobin F (HbF) immunostaining and chromosome abnormality, because HbF of erythroblasts was reportedly observed in MDS RA but not in AA. Most MDS/MDS-OL (47/48) had at least one positive marker. Among 11 AA cases, only two were positive for HbF. The present results suggest that the combination of these three markers is useful to discriminate MDS from AA.
Asunto(s)
Anemia Aplásica/diagnóstico , Anemia Refractaria/diagnóstico , Hemoglobina Fetal/metabolismo , Síndromes Mielodisplásicos/diagnóstico , Proteína p53 Supresora de Tumor/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Anemia Aplásica/genética , Anemia Aplásica/metabolismo , Anemia Refractaria/genética , Anemia Refractaria/metabolismo , Biomarcadores/metabolismo , Células de la Médula Ósea , Análisis Mutacional de ADN , ADN de Neoplasias , Diagnóstico Diferencial , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Cariotipificación , Masculino , Persona de Mediana Edad , Mutación , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismo , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Wilms' tumor 1 (WT1) is a useful marker for the diagnosis of acute leukemia and myelodysplastic syndromes (MDS). In the current study quantitative reverse transcription-polymerase chain reaction and immunostaining were used simultaneously to examine the relationship between WT1 RNA and protein level and also to evaluate WT1 as a tool to differentiate aplastic anemia (AA) and MDS refractory anemia (RA). Three types of WT1 messages (total, exon 5(+) and KTS(+)) and WT1 immunostaining of these diseases were analyzed. An increase of all three WT1 messages in high-grade MDS and acute leukemia was observed as compared with the normal control, whereas there was no significant difference in WT1 message between AA and RA, suggesting that WT1 message is not a good tool to discriminate AA and RA. No significant difference was observed between normal and RA, except for exon 5 message. Three WT1 message levels had a significant correlation, suggesting that the total WT1 message is sufficient for clinical practice. Positive immunostaining of WT1 was observed only in the portion of acute leukemia and overt leukemia (OL) transformed from MDS with a high WT1 message level, suggesting the relatively high detection threshold of WT1 protein with the immunostaining method.
Asunto(s)
Regulación de la Expresión Génica , Leucemia Mieloide Aguda/metabolismo , Síndromes Mielodisplásicos/metabolismo , ARN Mensajero/metabolismo , Proteínas WT1 , Adulto , Anciano , Anemia Aplásica/genética , Anemia Aplásica/metabolismo , Anemia Aplásica/patología , Anemia Refractaria con Exceso de Blastos/genética , Anemia Refractaria con Exceso de Blastos/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Diagnóstico Diferencial , Femenino , Humanos , Técnicas para Inmunoenzimas , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Masculino , Persona de Mediana Edad , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/genética , ARN Neoplásico/análisis , Proteínas WT1/genética , Proteínas WT1/metabolismoRESUMEN
Although aberrant promoter hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT) is a favorable prognostic marker in patients with diffuse large B-cell lymphoma (DLBCL), MGMT protein expression has not been thoroughly examined. The aim of this study was to evaluate the clinical implication of MGMT protein expression and its correlation with promoter hypermethylation of the gene. We investigated MGMT protein expression by immunohistochemical analysis of 63 DLBCL patients who received cyclophosphamide as part of multidrug regimens. In addition, promoter methylation of the MGMT gene was analyzed by a methylation-specific polymerase chain reaction assay, and correlations with chemotherapeutic effect and prognosis were statistically evaluated. Immunohistochemical assay results for MGMT protein were negative in 30.2% of patients with newly diagnosed DLBCL. Immunostaining results were closely correlated with the methylation status of the promoter. Promoter DNA methylation of the gene was not detected in 34 (81.0%) of 42 tumor samples determined to be MGMT-positive DLBCL by immunostaining and was detected in 15 (88.2%) of 17 cases of MGMT-negative DLBCL. Overall survival (OS) and disease-free survival (DFS) rates were significantly higher in MGMT-negative patients than in MGMT-positive patients (5-year OS, 81.3% versus 56.6% [P = .0375]; 5-year DFS, 66.3% versus 39.9% [P = .0121]). The combined rate for complete response (CR) plus unconfirmed CR was significantly higher in MGMT-negative patients (15/19, 79.0%) than in MGMT-positive patients (25/44, 56.8%) (P = .0488). A multivariate analysis showed that absence of MGMT expression was an independent prognostic factor for OS (relative risk, 4.09; P = .0258). Lack of MGMT protein expression is associated with aberrant promoter DNA methylation and appears to be a useful marker for predicting the survival of DLBCL patients.
