Immune cells protect the body from any infection and foreign invasions. However, it has been observed that in several types of tumor, immune system cells called macrophages help tumors grow. According to research, not all blood cells are lined by endothelial cells. These cells, also called cancer stem cells, can help tumors survive and grow. These are also the cells responsible for \u201cvascular mimicry,\u201d a phenomenon in which vessel-like structures are formed within solid tumors which supply them with nutrients. The researchers at The Scripps Research Institute found that in cancer, macrophages sometimes get reprogrammed to behave like cancer stem cells. They observed that macrophages played a role in vascular mimicry as they migrated to oxygen-deprived parts and formed vessel-like channels. Researchers believe these channels transported dissolved oxygen and glucose. According to them, these findings can help understand why in some cases tumor growth refuses to slow down and provide a new approach to treating cancer.<\/p>\n