NTN1 and neoplasm: For example, the expression of the truncated ΔN-netrin-1 (nucleolar N-terminal truncated isoform of netrin 1) was found to drive rDNA transcription and pre-rRNA processing and to increase the number of mature ribosomes in tumor cells, promoting the malignant phenotype (Delloye-Bourgeois et al., 2012).