We are aware that mechanistic details cannot be given yet; however, the in vitro response of diverse cancer cell lines to treatment with the truncated ITIH5-derived protein fragments (ITIH5161aa and ITIH5681aa) suggested a highly conserved and ITIH5 (signaling)-specific mode of action: (1) The ITIH5681aa fragment covering both the VIT and the vWA domain did not affect growth of benign mammary cells nor that of MDA-MB-231 single cell clones with strong overexpression of the full-length ITIH5 gene. The gene discussed is ITIH5; the disease is cancer.