Telomerase activity and related properties of normal canine lymph node and canine lymphoma

Telomerase activity (TA) and the expression of p16(INK4), telomerase reverse-transcriptase catalytic subunit (TERT) and proliferating cell nuclear antigen (PCNA) were analysed in lymph nodes from clinically normal dogs and from dogs with lymphoma. Telomere lengths were measured in 12 histologically normal lymph nodes. These data were related to the overall survival time of the lymphoma patients given chemotherapy, in an effort to identify prognostic significance of the measured variables. There was no significant difference between TA of normal lymph nodes (n = 16) and lymphoma lymph nodes (n = 6). PCNA expression was significantly higher in lymphoma (n = 30) than in normal lymph nodes (n = 10), but TERT expression was not. Expression of p16(INK4) was not significantly different between normal and lymphoma lymph nodes. TA and p16(INK4) expression were inversely correlated within the normal lymph nodes studied. Telomere lengths in normal lymph nodes were consistent with previous studies. No variables examined had any correlation with survival of the lymphoma patients given chemotherapy. The role of p16(INK4) in the regulation of TA warrants further investigation.