Although the KYSE30 in DEM did not express MMP9, there was a significant difference in the expression of CD44 between FFPE-ESCC and KYSE30/DEM, because all cells in the DEM samples expressed CD44, whereas only part of what are presumed to be disseminating cells involved with MMP9 signaling expressed CD44 in the FFPE-ESCC tumor tissue samples. Here, CD44 is linked to esophageal squamous cell carcinoma.