One of the things that makes cancer "successful" is its ability to hide from the immune system, and this can make it difficult to create effective cancer vaccines. This is partly because tumors create a solid ball of cells that make it hard for the immune cells to get inside, and once inside the environment either destroys the immune cells or stops them from working effectively.
Researchers from the University of Western Australia found that low doses of TNFα (tumor necrosis factor α) targeted to a pancreatic tumor enhanced the ability of immune cells (T cells) to get inside the tumor and helped them to survive by stabilizing the blood vessels in the tumor and improving blood flow.
The team combined this approach with an anticancer vaccine, and found that it improved the response to the vaccine. This is still early days, but this could be a route to improving responses to a range of cancer vaccines.