Abstract: Objective To study expression enhancement and purpose of Y14 and Upf1 in human breast cancer cell lines and human breast cancer tissue. Methods Immuocytochemistry and laser scanning confocal microscope（LSCM） were applied. Y14 and Upf1 were determined in human breast cancer cell lines（MCF-7、ZR-75-30、T47D、MDA-MB-435s、MDA-MB-453、MDA-MB-231）and breast epithelial cell line（HBL-100）.Results ①Y14 and Upf1 levels of breast cancer cells are obviously higher than the breast epithelial cell line（P＜0.05）.②Y14 and Upf1 levels of MDA-MB-231 are obviously higher than MCF-7.③The expression enhancement of Y14 and Upf1 levels are obviously higher in human breast cancer tissue. Conclusion The expression levels of Y14 and Upf1 in the breast cancer cells and tissue enhance obviously.

Key words: NMD, Y14, Upf1, human breast cancer cell line, epithelial breast cell line