"The immunological changes in the tumor at the start of treatment guide the efficacy of chemotherapy," said Dr. Guido Kroemer, from high school Gustave Roussy, Villejuif (France), on the occasion of the International Symposium "Advances and vaccine development", held at the research center Applied Medicine (CIMA) of the University of Navarra.

Conventional cancer treatments, such as chemotherapy and radiotherapy, have been shown in animal experiments and clinical observations to work partly through an immunological mechanism. According to Dr. Kroemer, "in our opinion, when the therapeutic agent kills the cancer cell, it becomes a vaccine that triggers an immune response against the residual cells."

Researchers at high school Gustave Roussy are trying to clarify what mechanisms chemotherapy uses to control tumor growth. "Normally in oncology, the question is why the treatment doesn't work. We have asked ourselves why some chemotherapies are so successful. There are two cases in which the treatment is particularly effective: breast cancer and colorectal cancer."

In his visit to CIMA, Dr. Kroemer explained that treatment of locally advanced breast cancer begins with 6 cycles of chemotherapy prior to surgical removal of the tumor. "We have shown that the immune profile of the tumor changes after first cycle chemotherapy. Specifically, local infiltration of T and cytotoxic lymphocytes into the tumor and tumor shrinkage due to immunosuppressive regulatory cells are observed. Therefore, it is possible to determine in advance which patients will respond successfully to treatment. If we can find out why it works we can apply this knowledge to therapies that don't work."