Patients with colon cancer have higher levels of antibodies against the Anisakis parasite, suggesting a possible association between the chronic inflammation caused by this parasitic infection and the development of this tumor.
A study led by the Foundation for the Promotion of Health and Biomedical Research of the Valencian Community (Fisabio) of the Ministry of Health and the Complutense University of Madrid (UCM), carried out with patients at the Arnau de Vilanova Hospital in Valencia, indicates that people with colon cancer have higher levels of antibodies against the Anisakis parasite, which can be found in fish.
“This means that these patients have come into contact with the larvae of this parasite to a greater extent than the rest of the population, which suggests an association between Anisakis and colon cancer,” explained Professor Carmen Cuéllar, researcher at the Department of Microbiology and Parasitology at the UCM.
Chronic inflammation resulting from persistent infection can cause DNA damage, increase the expression of oncogenes, reduce apoptosis (cell death process) and cause immunosuppression. These are some of the causes that can induce cancer. Therefore, the hypothesis of a relationship between Anisakis and cancer was raised, since cellular responses to the products released by Anisakis larvae could cause inflammation and DNA damage.
“More than three decades ago, it was even postulated that Anisakis could be related to gastric cancer, proving the tumorigenic potential of the products released by the larvae, but to date there was no evidence to suggest a relationship between this fish parasite and colon cancer,” says Dr. Cuéllar.
A parasitic infection contracted by eating fish
Anisakis is a nematode, a type of worm that parasitizes the stomach of marine mammals. The eggs produced by the females develop in water. Some marine crustaceans ingest these larvae and subsequently the fish that consume these crustaceans become infected.
Humans can become accidental hosts by consuming raw or undercooked fish. This foodborne parasite causes serious public health problems worldwide. Parasites located in the gastric or intestinal mucosa can cause gastrointestinal disorders. In addition, Anisakis can also cause reactions such as urticaria, angioedema, asthma and anaphylaxis.
“The T cells analysed in this study are part of the innate immunity and therefore reflect the immune response of patients. A decrease in these cells, as described in the article, not only shows the relationship between Anisakis and colon cancer, but also the decrease in the immune response of these cancer patients to this tumorigenic agent,” explains Dr Francisca López Chuliá, head of the Hematology and Hemotherapy research group at Fisabio-Hospital Arnau de Vilanova-Lliria in Valencia.
“We had already described correlations between some parasites and colon cancer and this study reveals the possibility of identifying people with a greater susceptibility to the disease”
To carry out the study, published in Parasitology Research, 92 patients with colon cancer diagnosed at the Arnau de Vilanova Hospital in Valencia were recruited, and 60 healthy people without cancer (control group) were included. First, blood cells were examined (analysis of T lymphocytes – cells that protect the body from infections and fight cancer – and evaluation of apoptosis) in the haematology laboratory of the Arnau de Vilanova Hospital.
Then, in the laboratory of the Department of Microbiology and Parasitology of the UCM, the antigen of Anisakis larvae extracted from blue whiting was prepared and the presence of specific antibodies was determined in the serum of people with colon cancer and in the healthy control group.
“In our group we had already described correlations between some parasites and colon cancer, even in the early and premalignant stages. This study reveals the possibility of identifying people with a greater susceptibility to the disease and the potential of generating new mechanisms to prevent it,” concludes Dr. Antonio Llombart Cussac, head of the Fisabio Clinical and Molecular Oncology group at the Arnau de Vilanova Hospital.
Sources: Complutense University of Madrid (UCM) and the Foundation for the Promotion of Health and Biomedical Research of the Valencian Community (Fisabio)
