[AgNOR in the pathologic differential diagnosis of tumors]

AgNOR staining technique was applied to facilitate the pathologic differential diagnosis of 74 breast tumors and 95 non-Hodgkin's lymphoma (NHL). The results showed that the mean AgNOR count per nucleus was significantly different between benign and malignant tumors (P less than 0.01). An AgNOR count per cell less than 3 indicated benign breast lesion and more than 5 implied malignancy. In NHL, AgNOR count that nucleolus less than 4 was indicative of low-grade while more than 6 of high-grade malignancy. In 45 NHL patients followed up, the AgNOR count/cell was high in 28 patients with short survivals than otherwise (17 patients). These observations suggest that the AgNOR could provide useful information about the nucleolus activity in hyperplastic and neoplastic conditions. Electron microscopically, argyrophilic protein was irregular in shape and highly stained with silver in the fibrillar centers and the dense fibrillar component in NHL tumor cells as compared to that seen in normal lymphocytes. This further implies that the NOR Proteins could be used as a marker of ribosomal DNA and its level of transcription is higher in the malignant tumors.