[The evaluation of cell proliferation in gliomas]. / Estimación de la proliferación celular en gliomas.

INTRODUCTION: The homeostasis of tissues depends on a strict control of cell growth, differentiation and death. Several proteins, which are involved on the regulation of the cell cycle, can suffer diverse alterations and produce an uncontrolled cell proliferation and the genesis of a neoplastic process. The assessment of cell proliferation is an useful method applied to Neuro-oncology in order to know the behavior of gliomas. DEVELOPMENT: This work is focussed on the analysis of different methods, all of them employed to study the cell proliferation: immunostaining of proliferating cell nuclear antigen (PCNA) and Ki-67, DNA content and ploidy by flow cytometry, in vitro incorporation of bromodeoxyuridine (BrdU) and the identification of apoptotic cells. The study of the DNA by flow cytometry establishes a relationship between ploidy and the prognostic of gliomas. The assessment of PCNA provides us with objective data about the proliferative activity of gliomas. Both Ki-67 expression and BrdU incorporation are also useful methods in the study of gliomas. CONCLUSIONS: In short, the most malignant gliomas are characterized by a high frequency of aneuploidies and high PCNA, Ki-67 and BrdU labelling indexes. All of these described methods can be used as prognostic markers complementary to the classic criteria employed nowadays.

Estimación de la proliferación celular en gliomas / Estimation of cell proliferation in gliomas

Introducción. La homeostasis de los tejidos depende de un estricto control de crecimiento, diferenciación y muerte celular programada. El paso de una fase del ciclo celular a otra está regulado por diferentes proteínas, las cuales pueden sufrir diversas alteraciones.Ello puede conllevar una desestabilización en el ciclo y desencadenar una proliferación celular incontrolada, que da lugar a la génesis de un proceso neoplásico. El análisis de la proliferación es un método útil en Neurooncología para conocer el comportamiento de los gliomas.Desarrollo. Se analizan diferentes métodos utilizados para conocer el comportamiento de los gliomas: identificación de proteínas del ciclo mediante anticuerpos antiantígeno nuclear de proliferación celular (PCNA) y ki-67, utilización de la citometría de flujo para la cuantificación del ADN y grado de ploidía, incorporación de bromodeoxiuridina (BrdU) en células tumorales in vitro y estimación de las células en apoptosis. El estudio del contenido en ADN mediante citometría de flujo establece cierta relación entre la ploidía y el pronóstico, y el análisis del PCNA proporciona una valoración objetiva sobre la actividad proliferativa de los gliomas. Asimismo, la inmunoexpresión de ki-67 o la incorporación de BrdU son también métodos útiles en el estudio de los gliomas. Conclusiones. Los gliomas de mayor malignidad se caracterizan por poseer una elevada frecuencia de aneuploidías, así como altas tasas de PCNA, ki-67 y mayor incorporación de BrdU. Todos estos métodos descritos pueden ser marcadores pronósticos complementarios a los criterios clásicos vigentes (AU)

Biologic parameters that correlate with the prognosis of human gliomas.

Much clinical and biologic data have been processed in the search for useful objective parameters to predict brain tumor behavior. Seventy cases of astrocytic glioma collected by a single clinical team were studied using a full complement of clinical procedures: follow up (7 years), histologic analysis, DNA content estimation, and cell kinetics by flow cytometry. Proliferating cell nuclear antigen (PCNA) was determined by immunocytochemical-coupling flow cytometry (PFC) and also by counting under light microscopy (PIHC). A statistical evaluation was carried out to establish the usefulness of several parameters for glioma prognosis. The cases were histologically classified as 14 low-grade astrocytomas, 20 anaplastic astrocytomas, and 36 glioblastomas multiforme. The survival curve showed significant differences between histologic groups. Diploid populations were more frequent in low-grade astrocytomas, and aneuploid tumors often had increased S-phase and proliferative fractions. The PCNA-labeled index (PCNA-LI) increased with malignancy and correlated with histologic grading (P = 0.01). The PCNA-LI and age segregated low- from high-grade astrocytomas (including anaplastic astrocytoma and glioblastoma multiforme), but none of the variables considered differentiated anaplastic astrocytoma from glioblastoma multiforme. The Cox regression test displayed significant values for age, histologic diagnosis, and PCNA determinations when considered in tandem. Discriminant analysis obtained a function integrating age and specifically PIHC-LI to help in the prognosis of doubtful cases. The results emphasize the importance of parameters integrating different variables in an attempt to provide an accurate prognosis, the most significant being age, histopathologic diagnosis, and the proliferative fraction determined by PCNA.

Expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptor-beta (PDGFR-beta) in human gliomas.

The growth of solid tumors is highly dependent on vascular proliferation. Vascular endothelial growth factor (VEGF), the main mediator of angiogenesis, and platelet-derived growth factor receptor-beta (PDGFR-beta), receptor for the potent mitogen PDGF, are two indicators of the angiogenic potential of human gliomas. We studied a series of 57 surgical biopsies of astrocytic neoplasms by immunohistochemistry to elucidate the relationship between tumor proliferation, quantified as Ki67-LI, and the expression of these two proteins. Ki67-LI increases throughout histological malignancy, although staining in endothelial cells has rarely been recorded. Elevated amounts of VEGF-positive tumor cells (VEGF-LI) were found in anaplastic astrocytomas and glioblastomas, mainly around areas of necrosis, cysts, or edema. Endothelium of blood vessels was consistently stained. PDGFR-beta positivity was found in glomeruloid formations and in tumor cells, excluding pilocytic astrocytomas. Multinucleated giant cells and perivascular tumor cells were positive in glioblastomas. In addition, peritumoral microglia-like cells were also stained in some cases. Statistical correlation was only found between PDGFR-beta and Ki67 LIs. In conclusion, VEGF as permeability factor is involved in the development of secondary neoplastic changes, whereas PDGFR-beta is directly correlated to proliferation indexes. Strong expression of VEGF and PDGFR-beta found in endothelium and tumor cells would seem to support a combined role in tumoral neoangiogenesis.