Using lymph node fine needle aspirates for gene expression profiling of canine lymphoma

Conventional classification schemes for canine lymphomas do not discriminate between phenotypically indistinct tumours that may exhibit differences in behaviour. Transcriptional profiling has the potential to afford objective clinically relevant stratification of canine lymphomas, and its sensitivity means that prognostic assays could be performed on tumour needle aspirates collected without anaesthesia. In this pilot study, we compared the expression profiles derived from surgical biopsies and fine needle aspirates of five lymphomas. The aspirates yielded expression profiles of equivalent complexity and strong similarity (median correlation Coefficient = 0.911) to those generated from corresponding surgical biopsies. Differences in gene expression observed between the two tissue sources suggest that the aspirates represent a purer source of lymphocytes. Despite the absence of a standardized sample collection protocol, the aspirates yielded expression profiles of consistently high quality suggesting that they represent a robust source of tumour tissue for a potential transcriptional profile-based prognostic assay for canine lymphomas.