NTN1 and carcinoma: Together with the fact that overexpression of netrin-1 in the mouse model described above shows two ‘time window’ effects – one during early phase of tumorigenesis, as illustrated by the adenomas and focal hyperplasias observed in these mice, and one late effect with the formation of adenoma-carcinomas in the APC/netrin-1 mice – this would point to regulatory functions of these dependence receptors at different times of colorectal tumorigenesis.