PLA2G7 and nasopharyngeal carcinoma: PLA2G7, on the other hand, was found to be induced at 24 hrs post co-culture and its expression was sustained thereafter (Figures 2–5) The majority of these cancer-promoting factors were also found to be expressed mainly in the THP-1 cells after co-culture with the NPC cells (Figures 5C, S4B, S5B).