We find minor differences between the classical and the variant form, confirm the specific expression of several already published genes such as CCND1 and ITGAE/CD103, and describe new ones, suggesting an activation of the non-canonical NF-kB pathway in some samples, and a post-germinal memory B cell origin of hairy cell leukemia cells. The gene discussed is NFKB1; the disease is hairy cell leukemia.