Relationship between Ricinus communis agglutinin-1 binding and nucleolar organizer regions in human gliomas

Histochemical staining using lectins from Ricinus communis (RCA-1), Arachis hypogaea, and Canavalia ensiformis was investigated in 40 human gliomas, three central neurocytomas, one human neuroblastoma cell line (IMR-32), and two normal brain tissues. Staining was uniform in low-grade gliomas, but heterogeneous in high-grade gliomas, particularly with RCA-1. The correlation between RCA-1 reactivity and cellular proliferative potential was investigated in 10 high-grade gliomas using a combined staining technique: the silver colloid method for nucleolar organizer regions (Ag-NORs) and histochemistry with RCA-1. The mean number of Ag-NORs counted on a simple preparation was significantly greater in the nuclei of RCA-1-negative cells than in those of RCA-1-positive cells (p < 0.001). The staining intensity of inflammatory cells was obviously higher than that of neoplastic cells, and therefore inflammatory cells were easily discriminated from neoplastic cells. Combined RCA-1 histochemical and Ag-NOR silver colloid staining revealed heterogeneous expression of RCA-1 receptor in high-grade gliomas with changes in Ag-NOR number. This result seems to show that high-grade gliomas express heterogeneous cellular carbohydrate structure and proliferative potential even within the same tumor.