CXCR4 and cancer: The expression of CXCR4 was mostly confined to the cytoplasmic membrane and cytoplasm of neoplastic cells (Fig. 1c, d, j) whereas CXCL12 was mainly located to cytoplasm and, in a lesser extend to cytoplasmic membrane of tumor cells (Fig. 1g, h, l) but also to tumor-associated macrophages and cancer-associated fibroblasts.