Breast cancer is the second largest cause of death in women, first being the skin cancer. Breast cancer is being treated by immunotherapy methods that boost the immune system to combat cancer. Adoptive Cell Transfer (ACT) is an immunotherapy approach that utilizes the cells extracted from the cancerous patient, converting them into a particular type of white blood cell through genetic modifications. The reformed white blood cell is then multiplied and injected back into the patient to target numerous cancer cells. This technique has only been successful in treating melanomas, so scientists were motivated to find more robust methods.
National Cancer Institute (NCI) in the United States advanced the ACT method to target cancers possessing higher levels of mutations and published the efficacy of this treatment in Nature Medicine. Tumor-infiltrating lymphocytes were employed by this new ACT method to particularly target tumor-cell mutations. These tumor-infiltrating lymphocytes were propagated into large numbers and returned to the cancer patient, eliciting a strong immune response against the cancer cells.
Further phase-2 clinical trials were performed on a metastatic breast cancer patient who was not responding to any other treatment. The DNA and RNA sequences from her normal and cancerous tissues were attained, which revealed 62 mutations exclusive to her cancer. Tests were conducted on different tumor-infiltrating lymphocytes to isolate the ones that recognize mutated proteins. Such lymphocytes were cultured to produce large numbers and inoculated back into the patient along with a medicine that inhibits the deactivation of these lymphocytes by tumors.
The patient possessing cancerous lesions in breast and liver responded positively to this novel ACT mutation-based method, depicting no signs of lesions after 14 months and no recurrence of cancer even after 22 months. ACT successfully treated colorectal and liver cancers, which could not be treated with the former ACT method.