Heterogeneity among human nasopharyngeal carcinoma cell lines for inflammatory cytokines mRNA expression levels.

Using polymerase chain reaction (PCR), we confirmed the expression of interleukin-1 α (IL-1 α ) by the human nasopharyngeal carcinoma (NPC) cell line C15 without contribution of either human IL-1β or mouse IL-1 α in the biological activity previously found in C15. However we showed that IL-1 α was not expressed in all NPCs. IL-1β and/or tumor necrosis factor (TNF)- α genes could also be activated, independently from the number of Epstein Barr Virus (EBV) copies harbored by the cells. Interestingly, the primary tumor C15 showed a profile of TNF-sensitive tumor while C17, C18 and C19 which were derived from metastasis have a typical profile of TNF-resistant cells. Furthermore, the inflammatory cytokines whose genes are classically induced by IL-1 and TNF were found expressed only in C17 and C19 suggesting another level of heterogeneity among NPCs.