RESUMO
OBJECTIVE: To develop a new ImmunoFISH technique for the study of oligodendrogliomas by combining a standard immunohistochemical stain using MIB-1 antibody with a standard FISH technique using commercial 1p36 and 19q13 chromosomal probes. METHODS: Validation was performed by two observers on a series of 36 pre-selected oligodendrogliomas and compared to the results previously determined by FISH alone. RESULTS: The ImFISH technique is easy to perform and to analyze and is no more time-consuming than the usual FISH technique. Our results show that the inter-observer reliability of ImFISH is high (κâ=â0.86 and 0.95 respectively for 1p and 19q). Compared to FISH, the ImFISH exhibits a very high sensitivity (â¼100%) and specificity (â¼90%) for 1p and/or 19q deleted cases. The sensitivity is high for normal cases (â¼85%) and imbalanced cases (â¼90%) with a specificity ranging between 50 and 85%. Finally, there were no significant differences between FISH and ImFISH results calculated on 60, 40 or 20 cells. CONCLUSION: Our study demonstrates the reliability of the ImFISH technique in oligodendrogliomas and emphasizes its advantage in poorly cellular tumoral specimen.
Assuntos
Anticorpos Antinucleares/metabolismo , Anticorpos Monoclonais/metabolismo , Neoplasias Encefálicas/genética , Cromossomos Humanos Par 19/genética , Cromossomos Humanos Par 1/genética , Hibridização in Situ Fluorescente/métodos , Oligodendroglioma/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/metabolismo , Cromossomos Humanos Par 1/metabolismo , Cromossomos Humanos Par 19/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Oligodendroglioma/metabolismo , Reprodutibilidade dos TestesRESUMO
BACKGROUND: There is a strong need to determine the best technique for O(6) -methylguanine-DNA-methyltranferase (MGMT) analysis, because MGMT status is currently used in clinical trials and occasionally in routine clinical practice for glioblastoma patients. METHODS: The authors compared analytical performances and predictive values of 5 techniques in a series of 100 glioblastoma patients who received standard of care treatment (Stupp protocol). RESULTS: MGMT promoter was considered methylated in 33%, 33%, 42%, and 60% of patients by methylation-sensitive high-resolution melting, MethyLight, pyrosequencing (with an optimal risk cutoff at 8% for the average percentage of the 5 CpGs tested), and methylation-specific polymerase chain reaction (MS-PCR), respectively. Fifty-nine percent of the samples had <23% (the optimal risk cutoff) of MGMT-positive tumor cells. The best predictive values for overall survival (OS), after adjustment for age and performance status, were obtained by pyrosequencing (hazard ratio [HR], 0.32; P < .0001), MS-PCR (HR, 0.37; P < .0001), and immunohistochemistry (HR, 0.43; P = .0005) as compared with methylation-sensitive high-resolution melting (HR, 0.52 P = .02) and MethyLight (HR, 0.6; P = .05). For progression-free survival (PFS), the best predictive values were obtained with pyrosequencing (HR, 0.35; P < .0001), methylation-sensitive high-resolution melting (HR, 0.46; P = .002), and MS-PCR (HR, 0.49; P = .002). Combining pyrosequencing and immunohistochemistry slightly improved predictive power for OS, but not for PFS. Poor reproducibility and interobserver variability were, however, observed for immunohistochemistry. CONCLUSIONS: Good prediction of survival in addition to high reproducibility and sensitivity made pyrosequencing the best among the 5 techniques tested in this study.
Assuntos
Glioblastoma/genética , O(6)-Metilguanina-DNA Metiltransferase/genética , Reação em Cadeia da Polimerase/métodos , Adulto , Idoso , Neoplasias Encefálicas/genética , Metilação de DNA , Feminino , Glioblastoma/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , O(6)-Metilguanina-DNA Metiltransferase/análise , Variações Dependentes do Observador , Prognóstico , Regiões Promotoras Genéticas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento , Adulto JovemRESUMO
INTRODUCTION: Histological, clinical and radiological features, and molecular genetic analysis are among the factors that have been considered in defining the prognosis of oligodendrogliomas (OD), but they have yielded conflicting results. The purpose of this study was to test out a scoring scale based on clinical, radiological, pathological and molecular features. MATERIAL AND METHOD: To identify factors with prognostic significance, we analyzed 87 treated patients with a histological diagnosis of OD. Of the parameters analyzed, age, onset, clinical status, radiological enhancement, histological necrosis, mitosis and chromosomal anomalies emerged as significant prognosis factors using univariate analysis. Multivariate analysis revealed age and chromosomal anomalies as independent factors of survival. RESULTS: The factors with a significant prognostic value were combined to determine which grouping factors best predict outcome. The proposed score is a pure number resulting from a combination of: 2 major factors: age and chromosomal anomalies (scored 3-0); 5 minor factors: onset, clinical examination, necrosis, mitoses (scored 1-0), and radiological enhancement (scored 2-0). According to our scale, 10 survival curves were produced for overall survival. Recursive partitioning of patients with the nearest score and outcome produced four groups with a significant difference in survival (p=10(-5)). The power of both the scale and the partitioned groups for predicting outcome was more accurate than the WHO and St Anne grading systems, and the molecular sub-classification. CONCLUSIONS: Our scale is a plausible way of classifying patients harboring intracranial OD according to expected survival.