Tolerating Tumors

Science Signaling  11 May 2010:
Vol. 3, Issue 121, pp. ec141
DOI: 10.1126/scisignal.3121ec141

Successful tumor growth depends on the ability of the tumor to escape detection by the immune system. Human cancers that express the chemokine receptor CCR7 are associated with tumor metastasis and poor prognosis, suggesting that CCR7-dependent signaling might lead to an immunotolerant tumor microenvironment. Shields et al. (see the Perspective by Zindl and Chaplin) studied a mouse melanoma model in which the tumors expressed varying amounts of the CCR7 ligand, CCL21. Tumors expressing CCL21 exhibited more aggressive growth and attracted a class of suppressive, rather than proinflammatory, leukocytes. Furthermore, the tumor microenvironment was rich in immunosuppressive cytokines and exhibited lymph node–like features. These features were not present in tumors that expressed low amounts of CCL21. Thus, tumor CCL21 expression promotes an immunotolerant tumor microenvironment, which is permissive for tumor growth and spread.

J. D. Shields, I. C. Kourtis, A. A. Tomei, J. M. Roberts, M. A. Swartz, Induction of lymphoidlike stroma and immune escape by tumors that express the chemokine CCL21. Science 328, 749–752 (2010). [Abstract] [Full Text]

C. L. Zindl, D. D. Chaplin, Tumor immune evasion. Science 328, 697–698 (2010). [Summary] [Full Text]