Tumor infiltration by chemokine receptor 7 (CCR7)(+) T-lymphocytes is a favorable prognostic factor in metastatic colorectal cancer

Abstract

The immune interactions occurring within the tumor microenvironment have a critical role in determining the outcome of colorectal cancer patients. We carried-out an immunohistochemical analysis of tumor infiltrating T-lymphocytes expressing chemokine receptor 7 (CCR7) in a series of colorectal cancer patients enrolled in a prospective clinical trial. We demonstrated that a high tumor infiltration score of this lymphocyte subset is predictive of longer progression free survival and overall survival.

Figure 1. The figure is representative of the opposite function of different tumor infiltrating immune-cells. (A and B) explain the pro-tumor activity of several infiltrating myeloid derived cells (such as neutrophils and macrophages) driven by a Th-17- mediated inflammation. This condition leads to the suppression of the adaptive antitumor immune response and, consequently, to a low tumor infiltration by either CCR7⁺ and FoxP3⁺ lymphocytes (double-low tumors). Conversely, (C and D) show a tumor highly infiltrated by both CCR7⁺ and FoxP3⁺ lymphocytes (double-high tumors). In this view, FoxP3⁺ may act by regulating tumor-dependent inflammation thus enhancing a tumor-specific response, leading to an efficient antitumor activity mediated by CCR7⁺ lymphocytes.