To this end, we carried out double IF staining using antibodies against pEGFR and each cell type-specific marker [VEGFR2 for endothelial cells, CD34 for EPCs, α-smooth muscle actin (α-SMA) for fibroblasts, and pan-cytokeratin (pan-CK) for tumor cells] in H460 xenograft tumors that relapsed after the Cs/Pc combinatorial treatment. Here, CD34 is linked to neoplasm.