LGR6 and breast cancer: LGR6 has been widely reported to serve as an important stem cell marker in multiple cancer types, which significantly contributed to carcinogenesis and progression of cancer.28, 29 Paradoxically, two literatures have reported that LGR6 potentially functioned as a tumor suppressor in colon cancer and breast cancer.24, 30 These findings suggest that the pro- and anti-tumor roles of LGR6 are tumor type dependent.