Due to changes in the expression of disulfide isomerases and Ero1, and the markedly high levels of oligomannose N-glycans in the parental NB cell lines (NB_1, BE(2)-C and BE(2)-M17), as well as other cancerous cells [17,18,20,21,22], it is arguable that cancer cells have higher levels of protein oligomannosylation due to disulfide bond formation(s) which decrease the rate of mannose removal from the oligomannose N-glycans and consequently their conversion to higher-order N-glycans. This evidence concerns the gene TXNDC15 and cancer.