Helminthic therapy and cancer
There are many different helminth species belonging to different phyla. Since these may use different mechanisms from each other, the effects of one species can not be generalized to others.
Some helminths cause cancer, while others protect against it[edit | edit source]


Helminths that have been identified as being carcinogenic include the fish-borne trematodes Opisthorchis viverrini and Clonorchis sinensis and the blood fluke Schistosoma haematobium, all of which are categorised by the International Agency for Research on Cancer as Group 1 biological carcinogens. [3] [4]
The helminths used for therapeutic purposes (NA, TT, TS and HD) are not carcinogenic (see Helminthic therapy safety), but one helminthic therapist has suggested that, since some solid mass tumours like to surround themselves with regulatory immune cells, it may be unwise to increase this cell population in patients with a history of solid mass tumours. [5]
See also
- 2025 Jan 8 Reinventing type 2 immunity in cancer (Nature review)
Cancer-promoting helminths[edit | edit source]
Three helminth infections have been classified as definitely carcinogenic to humans (group 1 carcinogens), namely Schistosoma haematobium, which is associated with cancer of the urinary bladder and the food-borne liver flukes Clonorchis sinensis and Opisthorchis viverrini associated with cholangiocarcinoma of the liver
- 2024 Mar 20 Convergence between helminths and breast cancer: intratumoral injection of the excretory/secretory antigens of the human parasite Toxocara canis (EST) increase lung macro and micro metastasis -- Full text | PDF
- 2023 Dec 14 From the discovery of helminths to the discovery of their carcinogenic potential -- Full text
- 2018 Mar 29 Pearls collections: What we can learn about infectious disease and cancer
- 2017 Jul Helminth infection-induced malignancy
- 2015 Nov 1 Why does infection with some helminths cause cancer? -- Full text | PDF
- 2014 Jul Controversies and challenges in research on urogenital schistosomiasis-associated bladder cancer -- Full text | PDF
- 2009 Nov Helminths and malignancy -- Full text
Protective role of helminths[edit | edit source]
Helminths may be able to elicit anti-tumor immune responses that can lead to protection from tumorigenesis, or even to cancer regression.
Helminth infection may limit the growth and dispersion of tumors.
Helminths reduce the level of IGF-1, which promotes the growth of certain tumors.
- 2020 Nov 4 Effect of anthelmintic treatment on serum free IGF-1 and IGFBP-3: a cluster-randomized-controlled trial in Indonesia -- Full text | PDF.
Effect of helminths by type of cancer[edit | edit source]
Breast cancer[edit | edit source]
- 2021 Feb 12 Hymenolepis diminuta-based helminth therapy in C3(1)-TAg mice does not alter breast tumor onset or progression -- Full text | PDF.

Colorectal cancer[edit | edit source]
- 2025 Aug 13 Global prevalence and correlation of intestinal parasitic infections in patients with colorectal cancer: a systematic review and meta-analysis -- Full text
- 2025 Apr 14 Helminth-induced immune modulation in colorectal cancer: exploring therapeutic applications -- Full text | PDF
- 2025 Feb 24 Natural Alternatives in the Treatment of Colorectal Cancer: A Mechanisms Perspective -- PDF download
- 2025 Jan 9 Immunotherapy in gastrointestinal cancers: current strategies and future directions - a literature review -- Full text | PDF
- 2014 Aug 24 Extraintestinal helminth infection reduces the development of colitis-associated tumorigenesis
Gastric cancer[edit | edit source]
Helminth infection may alter inflammatory responses to H. pylori and thus affect the progression of gastritis to gastric atrophy, dysplasia, and cancer.
The high prevalence of helminth infections in Sub-Saharan Africa may be responsible for a reduced risk of gastric adenocarcinoma.
- 2022 Dec 9 The impact of Helicobacter pylori and intestinal helminth infections on gastric adenocarcinoma and inflammatory bowel disease in Sub-Saharan Africa -- Full text | PDF
See also
Leukemia, myeloma and lymphoma[edit | edit source]
- 2024 Dec 31 The Impact of Cell-Intrinsic STAT6 Protein on Donor T Cell-Mediated Graft-Versus-Tumor Effect -- Full text | PDF
- 2023 Jun 9 After Bone Marrow Transplantation, the Cell-Intrinsic Th2 Pathway Promotes Recipient T Lymphocyte Survival and Regulates Graft-versus-Host Disease -- Full text | PDF
- 2019 Mar Intestinal Immune Conditioning with Helminths Employs Host T Helper 2 (Th2) Pathway to Induce Mixed Chimerism and Regulate Graft-Versus-Host Disease -- PDF
- 2018 Oct 5 Helminth-Induced Production of TGF-β and Suppression of Graft-versus-Host Disease Is Dependent on IL-4 Production by Host Cells -- Full text | PDF
- 2015 Feb 1 Intestinal helminths regulate lethal acute graft-versus-host disease and preserve the graft-versustumor effect in mice -- Full text | PDF (Helminths improve the outcome of bone marrow transplantation in mice)
See also
- 2021 Aug 27 Novel Insights Into the Mechanism of GVHD-Induced Tissue Damage -- Full text | PDF
Pancreatic cancer[edit | edit source]
- 2020 Oct 29 Historical analysis of inverse correlation between soil-transmitted helminthiasis and pancreatic cancer -- Full text | PDF
Papillomavirus induced cervical cancer[edit | edit source]
- 2018 Aug 1 Hookworm exposure decreases human papillomavirus uptake and cervical cancer cell migration through systemic regulation of epithelial-mesenchymal transition marker expression -- Full text | PDF
Cancer has been linked to inflammation, which is controlled by helminths[edit | edit source]
Helminths and their products may potentially treat cancer[edit | edit source]
The scientific literature reveals that various cancer types have shown promising responses to parasite therapy in both in vitro and in vivo animal studies.
Helminths exert antitumor effects via several mechanisms of action.

The following anecdotal report suggests a positive contribution by NA to treatment in one case of cancer.

- And an update three years later.
- Re-innoculated myself with 10 N. americanus (NA) on July 13th 2023, after successfully hosting NA back in late 2019 and into 2022. My goal back in 2019 and now remains the same. Combatting my hereditary condition known as FAP (familial adenomatous polyposis) which fueled my diagnosis of Stage IV colorectal cancer five years ago, at the age of 30. Within the first 3-4 months; my body, spirit, overall health - and cancer prognosis - sobered up! I was also put on (just before inoculation) a last ditch effort immunotherapy that had "little hope of prolonged life". This PD-1 inhibitor treatments, in my opinion, might have worked synergistically with the NA response to my immuno profile. I credited the NA on two things; 1) helping my body repair DNA and address inflammation from my flawed inherited genes, & 2) promote pathways that helped go after my tumors littered throughout my lymph nodes, liver, diaphragm, and colon. Specifically interleukin pathways and the release of high amounts of eosinophils (EOs) which are known to interrupt colorectal cancer cells. This also helped me during my first reoccurrence with the disease in early 2021, while on an experimental trial in which I was about the best (of very few) positive responses. I killed off my previous colony in favor of a highly recommended protocol involving a common ingredient in dog dewormer while in remission in October of 2022, my last NA innoculation before killing off the NA was in April 2022. Fast forward to now (2023) I was recently re-diagnosed with cancer after another year of remission. My last CT scan showed some growth in my lymph nodes with no additional spread. Hoping this works with my last standard of care treatment. [8]
Worm-derived molecules could be potential candidates for anti-cancer drugs[edit | edit source]
- 2024 Sept 17 Anisakis extracellular vesicles elicit immunomodulatory and potentially tumorigenic outcomes on human intestinal organoids -- Full text | PDF
- 2022 Jan-Mar Anti-Tumor Effect of Marshallagia marshalli Somatic Antigen on Inhibition Cell Growth of K562 -- Full text | PDF
Molecular mimicry between parasites and cancer[edit | edit source]
- 2025 May 22 Molecular mimicry between parasites and cancer: a novel approach for developing cancer vaccines and therapeutic antibodies -- Full text | PDF
Infection with other microorganisms may also help to reduce cancer risk[edit | edit source]

BCG vaccination in infancy confers a survival advantage for melanoma patients, and vaccination of adults against yellow fever may have a similar effect.
Infection with the feline parasite, Toxoplasma gondii, stimulates the body to produce natural killer cells and cytotoxic T cells, which wage war on cancer cells.
Rather than the presence of infectious microorganisms increasing cancer risk, a lack of them may be the greater problem.

See also
- 2025 Jul 29 Bridging the gap for diverse applications of parasites as advanced cancer therapeutics: current progress and future directions -- Full text | PDF
Anthelmintic drugs may be used in cancer treatment[edit | edit source]
This does not mean that terminating any helminths that a cancer patient may be hosting will help to treat their cancer.
When an anthelmintic drug such as mebendazole (Vermox) is used in cancer treatment, it is not because of its worm-killing effects, but because of its ability to act directly on cancers, blocking tumor growth and spread, inducing apoptosis, and increasing sensitivity to other anti-cancer therapies. [11]
However, the use of an anthelmintic as part of a patient’s cancer treatment would prevent that patient from hosting helminths while they remain on that treatment.
When a helminth, itself, gets cancer[edit | edit source]
This rare case in which a man died after a tapeworm inside him developed cancer, involved a helminth that is not used in therapy.
For a discussion about this case, see this support group thread.
Reviews and meta-analysis[edit | edit source]
- 2025 Jul 29 Bridging the gap for diverse applications of parasites as advanced cancer therapeutics: current progress and future directions -- Full text | PDF
- 2025 Jan 8 Reinventing type 2 immunity in cancer (Nature review)
- 2024 Oct 9 The role of helminths and their antigens in cancer therapy: insights from cell line models -- Full text | PDF
- 2024 Oct 5 Parasites revive hope for cancer therapy -- Full text | PDF
- 2024 Jul 29 Mining parasites for their potential as novel therapeutic agents against cancer -- Full text
- 2024 Mar 29 How tapeworms interact with cancers: a mini-review -- Full text | PDF
- 2018 Sep 28 Parasites as negative regulators of cancer -- Full text | PDF