The immunostaining of residual tumors showed a high degree of CD56+ tumor-infiltrating NK cells, and a marked reduction of two stemness markers (SOX-2/ALDH2) expression in treated tumors, compared to untreated controls (Fig. 5c), confirming the CSC-targeting ability of locally administered NK cells in an organ-specific microenvironment. Here, ALDH2 is linked to neoplasm.