FGR is not only connected to NFIB, but FGR also shares a protein–protein interaction with IGLL5 and a gene–gene interaction with FCRL1. FCRL1 expressed in a majority of chronic lymphocytic leukemia, follicular lymphoma, hairy cell leukemia, and mantle cell lymphoma38 and might play an important role in the onset of these malignancies. The gene discussed is FCRL1; the disease is hairy cell leukemia.