Usually, Macrophage infiltration in cancer (TAM-tumor associated macrophages) predicts a poor prognosis. Because most of the macrophages in tumor are M2-like macrophage which suppress the immune responses by secreting many immunosuppressive cytokines (like IL10,...), so the immune cells can not eliminate the cancer. There is a hypothesis that if we can find a way to convert those M2-like macrophages into M1, that could be a new cancer therapy strategy.
The impact of tumor-infiltrating macrophages depend on several parameters, including tumor type, macrophage subtype and several other. So far, macrophage have been detected mainly as CD68+ cells, all confounded, which is why the literature is full of contradictory reports. You can perhaps get a clearer picture here http://www.ncbi.nlm.nih.gov/pubmed/23243596
Tumor associated macrophages (TAMs) can produce proangiogenic and prometastatic factors. Similar to Th1 and Th2 cells, macrophages can be grouped into M1 and M2 types.
Usually macrophage infiltration is a predictor for poor prognosis and is typical for how stroma supports tumor growth.
CD208 (DClamp) and CD68 are markers of the LAMP family wich can be seen on macrophages and mDCs. Both markers are in opposition in the cell according to the stage of maturation of the cell.
The presence in the tumor of CD68 + cells is poor prognosis.
While the presence of cells of the same lineage, which are DCLAMP + is very good prognosis. We can observe these cells in the tumor as well as in the draining lymph node.