RTN4 and breast cancer: The findings from this study demonstrate: (a) NgBR is highly expressed in ER positive and Her2 negative IDC breast cancer, whereas Nogo-B is ubiquitously expressed in IDC; (b) expression of NgBR is correlated with survivin expression in IDC as well as in later stages of breast cancer; (c) NgBR is essential for estradiol-induced survivin expression in ER positive breast tumor cells; (d) and finally, NgBR is also required for estradiol-stimulated ER positive breast tumor cell growth.