ALK3QD reduces intraperitoneal tumour formation. Female CD-1 nu/nu athymic nude mice were injected intraperitoneally with a suspension of 5 × 105 cells (either 429T-ALK3QD or 429T control cells), resulting in four groups of fifteen mice (each cell line with or without Dox-containing chow). (A) Fewer Dox-treated mice injected with 429T-ALK3QD cells developed detectable tumour lesions throughout the peritoneal cavity when compared with Dox-treated 429T-injected mice. (B) ALK3QD transgene expression in tumours that formed in nude mice was confirmed by RT-PCR analysis of total RNA with human GAPDH mRNA expression serving as a control for xenograft material present in each sample. (C) Tumour specimens isolated from 429T-injected and 429T-ALK3QD-injected mice fed a Dox-containing or normal chow diet were analyzed histologically by H&E staining. Tumour implants from the peritoneal wall were adherent to the surface of smooth muscle in Dox-treated 429T-ALK3QD-injected mice, whereas localized invasion was evident in specimens from the other groups of mice. 100 × original magnification.