Our results indicate clearly that IFN-γ transduction could merely stimulate P-NPC cells constitutively secreting low basal levels of IL-6 to produce much higher levels of IL-6, but could not stimulate BM-NPC cells that have constitutively been able to secrete this cytokine and IFN-γ in higher levels, to further release additional IL-6. This evidence concerns the gene IL6 and nasopharyngeal carcinoma.