ALDH1A1 and neoplasm: Immunohistochemical staining revealed that there was no significant difference in ALDH1-positive rate between tumors derived from AMOC-2 ALDH1high cells and tumors derived from AMOC-2 ALDH1low cells, whereas the tumor derived from RMG-1 ALDH1high cells showed significant higher ALDH1 positive rates than that of tumor derived from RMG-1 ALDH1low cells (Figure 4D).