NAC prevents in vivo tumoral development. (a) Tumor weight in mice treated orally with 5 g/L NAC. B6D2F1 mice were injected with L1210 cells, treated (+) or not (−) with NAC, and the tumor weight, determined at day 11, was expressed in g (mean ± SEM, n = 50). Bars represent the mean weight. (b) Survival of mice injected with L1210 and treated (•) (n = 50) or not (○) (n = 50) with NAC. Results are expressed in percent of animal survival. Arrows represent the time of L1210 cell injection. (c) Effect of NAC on membrane TNFα expression by cells from the tumors. Membrane TNFα was determined by FACS on cells from the tumors from mice treated (+) or not (−) with NAC. Results are expressed as a percentage of cells expressing membrane TNFα (mean ± SD, n = 5). *Means P < .05. (d) Cytotoxic activity of PFA-fixed spleen cells from NAC-treated mice (+) and not treated mice (−) was determined against L1210, in the presence (▪) or not (□) of a neutralizing anti-TNFα Ab. Results are expressed in percent of cytotoxicity (mean ± SD, n = 8). *Means P < .05.