Immunohistochemical studies show that the large tumour cells within proliferation centres show increased expression of Ki67, CD20, CD23, CD38, IRF4, survivin (BIRC5), BCL2 and MYC compared to small lymphocytes outside proliferation centres, and upregulate NOTCH, CD40 and BAFF signalling pathways leading to NF‐kB activation (Patten et al, 2008; Giné et al, 2010; Herreros et al, 2010; Gibson et al, 2015; Onaindia et al, 2015). The gene discussed is CD40; the disease is neoplasm.