Prognostic value of argyrophilic nucleolar organizer region (AgNOR) staining in feline intestinal lymphoma.

Limited information is available on prognostic factors for cats with lymphoma. The quantity of argyrophilic nucleolar organizer region (AgNOR) proteins can be used as a measurement of cellular proliferative activity. To determine if AgNORs were of prognostic value for feline intestinal lymphoma, the silver staining technique was performed on paraffin-embedded sections of 31 cases. Mean number of AgNORs per nucleus ranged from 1.02 to 4.32. Twenty-four (78%) cats had small AgNORs and 7 (22%) had large AgNORs. All cats were treated identically with a combination chemotherapy protocol. Response to chemotherapy was 87%. Median remission duration and survival times were 120 days and 201 days, respectively. No significant correlation was found between mean number of AgNORs per nucleus or AgNOR size and remission rate, remission duration, or survival time. This study indicates that AgNOR staining is not a useful prognostic factor for cats with intestinal lymphoma.