However, the frequency of tumorsphere-forming cells was markedly decreased in PODXL-silenced MDA-MB-231 breast cancer cell line and, conversely, its overexpression in luminal-like MCF-7 breast cancer cell line, a low metastatic cell line expressing low levels of endogenous PODXL, resulted in increased tumorsphere formation [80]. Here, PODXL is linked to breast cancer.