Journal of Dental Medicine

Nucleolar organizer regions (NORs) are loops of rDNA, which in human, occur on the short arms of five acrocentric chromosomes, namely, 13, 14, 15, 21 and 22. NORs are usually demonstrated by binding If their associated proteins (NORAPsO to silver (Ag+) ions. The reaction is called AgNORs. It has been determined that, the number and the size of NORs is related to the proliferative activity and grade of malignancy. This has led to the application of AgNOR method to a wide range of diagnostic problem cases, including breast, salivary glands and lung malignant neoplasms.The purpose of this study was to determine the value of AgNOR method in assessment of the grade of malignancy in non- Hodgkin's lymphoma of head & neck, which often is difficult and essentially important in relation to the prognosis and treatment.41 cases of paraffin embedded specimens of NHL, which were classified by working formulation system,were selected and then AgNORs method was applied on them.AgNORs were enumerated for all 41 cases of NHL (Standard Crocker).The mean AgNORs in 11 cases of low grade 15 cases of intermediate grade and 15 cases of high grade NHL was 1.66 (SEM= 0.098), 2.25 (SEM= 0.084) and 5.19 (SEM= 0.11), respectively.In analysis of variance and multiple comparisons, a significant difference was found between the three groups of NHL (P<0.000I).It is concluded that the AgNORs, as a reliable method, could be used in differentiation of low,intermediate and high grade NHL in head and neck area.