Canine T cell lymphoma is associated with high-frequency Helios expression.

<p>Helios expression by cells harvested by fine needle aspiration from the lymph nodes of dogs with B cell lymphoma (BCL), T cell lymphoma (TCL), reactive hyperplasia (RH) and mast cell tumors (MCT) was examined as a marker for thymic Tregs, but the unexpectedly high frequency of Helios⁺ events in a few B cell and several T cell lymphoma cases suggested neoplastic expression of this marker. Median frequency of Helios expression was significantly different between the groups (p = 0.00003). Representative dot plots for BCL and TCL cases, with their respective isotype control stains, is shown (A), followed by box-and-whisker plots summarising the data (B). (For key to symbols, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105027#pone-0105027-g002" target="_blank">Figure 2</a>).