We examined two cancer stem cell markers: ALDH1-A1 and CD44 in the tumors and observed an increase in ALDH1-A1-positive cells in tumors compared to Plexin-B3 knockdown cells, suggesting that the loss of Plexin-B3 may directly or indirectly check cell proliferation and enhance cancer stemness in PC malignancy. This evidence concerns the gene ALDH1A1 and cancer.