NTSR1 and colonic neoplasm: NTR1-positive HT-29 colon cancer cells revealed increased growth at concentrations of 0.07–2.08 nM Lys8-ψ-Lys9NT (8–13); however, proliferation was significantly inhibited at 16.67 nM Lys8-ψ-Lys9NT (8–13), similar to BxPC-3 cells.