ER-Gli1-ALDH1 axis in TNBC Go Yoshida, School of Medicine, Keio University 9 July 2014 Estrogen receptor (ER) expression was reported to be positively correlated with glioma-associated oncogene homoglog 1 (Gli1) and ALDH1 both in vitro and in vivo. The authors mentioned in Discussion that triple-negative breast cancers (TNBCs) include a large number of CD44 (+) /CD24 (-) cancer stem cell, although ER-Gli1-ALDH1 axis does not exist. In contrast, there is a report that the Gli1 expression in TNBCs was significantly higher than in breast cancers other than TNBCs (Oncol Lett. 2011 Sep 1;2(5):995-1001.). That is why ER is likely to activate non-canonical Shh signaliing pathway. Competing interests No Competing Interests Exist.