ABSTRACT
Background: Patients with Glioblastoma multiforme (GBM) have a five years survival of less than 5%, but the response to chemotherapy with alkylating agents can vary depending on the methylation status of O6-methylguanine-DNA-methyltransferase (MGMT). Genetic testing has limitations for routine use, while immunohistochemistry (IHC) offers a fast and affordable technique but with heterogeneous results in the literature. Aim: To evaluate MGMT expression by IHC in tumor tissue of Chilean patients with GBM. Material and Methods: Tumor samples of 29 patients with a pathological diagnosis of GBM were studied. We performed IHC staining and manual analysis of positive and negative cells for MGMT expression. A cut-off of at least 10% of cells expressing MGMT was used. Demographic and clinical features of patients were obtained from clinical records. Results: The median number of cells counted per case was 692 (interquartile range [IQR] 492-928). Fifteen cases (52%) were positive for MGMT expression. Median overall survival was 5.3 months (IQR 3.4-12-8). The effect of MGMT expression on the therapeutic response was not studied since only 3 patients received chemotherapy. Conclusions: Our results are similar to international reports, but we were not able to determine the association between MGMT expression and therapeutic response.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Brain Neoplasms/enzymology , Biomarkers, Tumor/metabolism , Glioblastoma/enzymology , O(6)-Methylguanine-DNA Methyltransferase/metabolism , Prognosis , Brain Neoplasms/genetics , Immunohistochemistry , Biomarkers, Tumor , Gene Expression Regulation, Neoplastic , Chile , Survival Rate , Retrospective Studies , Glioblastoma/genetics , O(6)-Methylguanine-DNA Methyltransferase/geneticsABSTRACT
El carcinoma epidermoide del hueso temporal es una neoplasia derivada de células epidérmicas del estrato espinoso, y que dado su baja incidencia, y presentación clínica similar a un cuadro de otitis media crónica colesteatomatosa, su diagnóstico es habitualmente tardío. El estudio del carcinoma epidermoide del hueso temporal se realiza con tomografía computarizada, la que evidencia erosión ósea. Sin embargo, existen distintos diagnósticos diferenciales, tanto malignos como benignos, que pueden provocar hallazgos similares en la tomografía computarizada. La resonancia magnética (RM) es un método de exploración de gran valor complementario para el estudio del carcinoma de oído medio. La RM con secuencia de difusión HASTE ha surgido como herramienta de estudio en patología de hueso temporal, tales como colesteatomas y teratomas de oído medio, pese a esto, no existen reportes en la literatura de la presentación imagenológica del carcinoma epidermoide de hueso temporal utilizando este método. En este artículo se presenta un caso clínico de una paciente con carcinoma epidermoide de oído medio, cuyo estudio preoperatorio incluyó RM-HASTE. Aun cuando se requiere un mayor número de casos para establecer el patrón imagenológico, se concluye que esta técnica es de utilidad para diferenciar este tumor de otitis media crónica colesteatomatosa.
Squamous cell carcinoma of the temporal bone (SCC) is a malignancy originated from epidermis spinous cells. Its low incidence and similar presentation to cholesteatomas, contributes to its late diagnosis. The most widely used study for this tumor is computed tomography (CT), which mainly evidences erosion of the temporal bone. There are several other diagnoses, malignant and benign, that could provoke similar findings at the CT. Magnetic resonance imaging (MRI) is a method of great value to study SCC. MRI with HASTE diffusion sequence has recently emerged as an important tool in the study of temporal bone pathologies, such as cholesteatoma and middle ear teratoma, despite this, there are no reports in the literature of the imaging presentation of SCC using this method. This article presents a clinical case of a patient with SCC, in whose preoperative study was performed HASTE-MRI. Although a larger number of cases are required to establish an imaging pattern, it is concluded that this technique is useful to differentiate this tumor from middle ear cholesteatomas.