High FCGR2B Expression Can Identify Low-tumor-burden Follicular Lymphoma Patients Who Do Not Require Any Antilymphoma Therapy for a Long Term.

Spontaneous regression or a long-term lack of obvious progression is often observed in patients with low-tumor-burden (LTB) follicular lymphoma (FL). However, conventional prognostic risk models are unable to precisely identify the patients who will not require any antilymphoma treatment for a long term, especially at diagnosis. In this study, we identified genes whose expression levels were associated with the clinical outcome of LTB FL and verified their prognostic value using immunohistochemistry. Because the tumor microenvironment may influence FL pathogenesis, we used digital expression profiling to quantify the expression of 730 immune-related genes extracted from tumor tissue specimens collected from 55 untreated patients with LTB FL. Five genes were identified as potential transcriptomic predictive markers. Among these, FCGR2B, an inhibitory FC gamma receptor, was immunohistochemically stainable and identified as a reliable immunohistochemical prognostic marker mainly expressed in tumor cells but not in the surrounding reactive cells. Our findings could help identify patients with LTB FL who do not require any antilymphoma treatment for the long term.