All human and canine cell lines tested in this study indicate that high levels of the p65 subunit and the p50/105 subunit are expressed whilst the p52/100 subunit is virtually undetectable, suggesting that the classical canonical NF-κB pathway is predominantly activated in these non-Hodgkin's lymphoma lines rather than the alternative pathway. This evidence concerns the gene NFKB1 and non-Hodgkin lymphoma.