ALDH1A1 and neoplasm: Similarly, the staining of lung sections from PLGA-PEI-si-m/hVDAC1-B- and PLGA-PEI-si-NT-treated mice with antibodies specific to ALDH1 member A1 (ALDH1A1) showed that in the tumor-free areas, the expression levels of ALDH1A1 were higher relative to its levels in the tumor areas, which showed no significant staining (Figure 5B).