CD34 and neoplasm: We demonstrated that CD34 was abundantly expressed on the cell surface of PKAP+ tumor cells, as shown in Figure 3D. Meanwhile, using IHC staining, we also found upregulated CD34 protein expression in PDAC tissues derived from PKAP+ PDAC mice compared to PKP+ mice, and confirmed that CD34 was located in the cell membrane and cytoplasm of PDAC lesions in PKAP+ mice, as shown in Figure 3E. Thus, we concluded that the expression levels of CD34 in PKAP+ PDAC tissues were significantly higher than PKP+ tumors, implying that the inactivation of APC may lead to induced CD34 expression in PDAC.