Salmonella usually causes food poisoning, but in 2019, 71 year old Canadian Irit Barbour volunteered to drink a bottle of liquid containing 1 billion active Salmonella typhimurium as the last resort to fight pancreatic cancer. At that time, pancreatic cancer had spread to other organs in her body, and she could only live for a few months. The Salmonella she drank has been genetically modified to attack cancer cells and has less toxicity to other parts of the body than ordinary Salmonella. Barber was the first person in the world to try Salmonella therapy while undergoing chemotherapy, and the results showed that her tumor had shrunk to 10% of its original size. The website of New Scientist magazine in the UK recently reported that new research has shown that some bacteria and fungi residing on tumors can affect the progression and treatment of cancer, and may become a new weapon in the arsenal of anti-cancer weapons. Some related drugs are currently undergoing clinical trials, and these microorganisms can penetrate into areas that are difficult to reach with existing therapies such as chemotherapy, providing alternative methods for attacking tumors. Tumors are the "happy nest" of bacteria. Bacteria, fungi, viruses and other microorganisms inhabit in people's intestines and affect human health in a variety of ways. In 2020, Irana Leviathan and her colleagues from the Weizmann Institute of Science in Israel reported in the journal Science that after analyzing over 1000 human tumor samples, they found that the tumors were also filled with microorganisms. Through gene sequencing, Leviathan identified bacteria in eight types of tumors in humans, including the breast, brain, lungs, skin, bones, ovaries, pancreas, and colon. Colon and breast tumors typically carry more bacteria, and they even found unique bacterial populations in each type of cancer. In the same year, the Leviathan team released explosive news: they also discovered fungi in the 8 types of tumors they had previously studied. The team led by Ilian Iliev of Cornell University in New York, USA, also published a paper in the journal Cell, saying that after studying gastrointestinal tumors, lung cancer and breast cancer, they found that these tumors often contain candida, blastomyces, Malassezia and other fungi. There are various reasons why microorganisms can be used to combat tumor attraction, but scientists are increasingly aware that their presence can affect the progression and treatment of cancer. For example, Ilyev et al. found that higher levels of Candida in gastrointestinal tumor cells are associated with higher pro-inflammatory gene activity, cancer metastasis rate, and lower cancer survival rate. In addition, Fusobacterium tuberculosis can promote the occurrence of cancer, accompany its spread to other parts of the body, and inhibit its response to chemotherapy. For decades, scientists have known that human papillomavirus (HPV), hepatitis B virus (HBV) and other viruses can trigger the formation of cancer, and HPV and HBV vaccines have also been developed to help prevent the occurrence of related cancers. Robert Holt from the Cancer Research Institute in British Columbia, Canada, said that people may be able to "follow the example" and develop vaccines against oncogenic bacteria, using them to slow down tumor progression, strengthen the response to chemotherapy, and even prevent tumor formation from the beginning. Holt's team is specifically developing a targeting tool