CD24 and gastric cancer: Previously, gastric TICs have been identified by using CD44 [11], CD44 and EpCAM [12], CD44 and CD24 [13], CD44 and CD54 [14], CD90 [32], and aldehyde dehydrogenase 1 [33] as markers, but CD49f has not been used to detect TICs in gastric cancers.