Figure 7.

Model of CX3CL1-induced breast carcinogenesis in ErbB2 transgenic mice. We propose that CX3CL1 is not involved in tumor initiation, which is probably mediated by ErbB2 mutagenesis. In this model, CX3CL1 would promote the progression of small or preneoplastic lesions in the mammary gland by enhancing ERK pathway activation through transactivation of the ErbB receptor family. Direct activation of this mitogenic pathway by PyMT would overcome the effect of CX3CL1 on breast tumorigenesis in Tg-PyMT mice. HB-EGF, heparin-binding EGF; AR, amphiregulin, ADAM, a disintegrin and metalloprotease.