We speculate that this is due to an effect of other mediators of migration and metastasis (for instance Metastasis-associated in colon cancer 1 (MACC1) that is also expressed in some AGE/S cell lines [41] or SMAD4 that is altered in NCI-N87 cells (see Table 1)) that maintain the migratory capacity of NCI-N87 cells independently of S100A4 expression. Here, SMAD4 is linked to cancer.