Nucleolar organizer regions in various human brain tumors

Abstract

Nucleolar organizer regions (NOR's) are loops of deoxyribonucleic acid (DNA) which transcribe to ribosomal ribonucleic acid (RNA) by RNA polymerase I. They possess vital significance in the ultimate synthesis of cellular proteins. A silver colloid staining technique for demonstration of NOR-associated proteins (Ag-NOR's) was applied to paraffin-embedded sections from 128 varied brain tumors and to chromosomal preparations from cultured brain-tumor cells. There was a statistically significant difference in the mean number of Ag-NOR's per nucleus between low-grade tumors (1.98/nucleus) and high-grade tumors (2.95/nucleus). It is suggested that the mean number of Ag-NOR's may represent the proliferative potential of brain tumors. Furthermore, high-grade tumors usually showed relatively large Ag-NOR's in a scattered distribution. In chromosomal preparations, the cultured cells displayed five to 12 Ag-NOR's on acrocentric chromosomes. Five of eight cell lines examined demonstrated ectopic Ag-NOR's. This simple staining technique can be easily applied to routinely processed paraffin-embedded sections and will become a useful tool for quick estimation of the proliferative potential of human brain tumors.

Invasive meningioma: A tumour with high proliferating and ?recurrence? potential

“…Detailed discussions on the methodology of PCNA [13,14,26] and AgNORs [10,15,25] are given elsewhere. Comparison of the results of this study with those reported in literature on the PCNA index [17] and AgNOR index [9,24,28] in meningioma, showed that the values for NON and benign meningiomas were almost equal. Comparison of the results of this study with those reported in literature on the PCNA index [17] and AgNOR index [9,24,28] in meningioma, showed that the values for NON and benign meningiomas were almost equal.…”

Determination of growth fraction and cell density to evaluate the potential growth of human oligodendroglial and astrocytic tumours

“…If correctly applied, the AgNOR technique should allow a good evaluation of the cell cycle time. By way of a reminder, nucleolar organizer regions are loops of DNA that are transcribed to RNA by RNA polymerase I, and are of vital signi®cance in the ultimate synthesis of cell proteins (Shiraishi et al 1991). These NOR can be histochemically revealed by means of argyrophilic (Ag) staining (hence the AgNOR designation).…”

“…Finally, some markers use the speed with which cycling cells produce daughter cells. The argyrophylic nucleolar organiser region (AgNOR) technique could be used for this kind of marker (Bigras et al 1996;Carbajo et al 1993;Maier et al 1990;O È fner et al 1992;Shiraishi et al 1991).…”

Prognostic significance of nucleolar organizer regions (NORS) in malignant melanoma

“…Within the last lew yeais, AgNOR staining has been used to study cutaneotis neoplasms (16, 26) and other solid tumors, including breast (33), prostate (34), brain (35,36), liver (22), and colon carcinomas (23), lymphomas (27), and osteogenic sarcomas (37). In 1987, Crocker et al (1) published their sttidies cm AgNOR counts in cntaneons melanocytic lesions and showed a significant difference between nevi (mean 1.2/nucletis) and cutaneous melanoma (mean 7.9/nticlens).…”