Helminthic therapy and cancer

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Some helminths cause cancer, while others protect against it

In spite of having parasites that are classified as inducers and promoters of some neoplasms, others are reported as negative regulators of cancer.” [1]

Emerging evidence indicates that certain parasites… are causative agents of malignancies such as bladder cancer caused bv schistosomes and cholangiocarcinoma by liver flukes… On the contrary, some parasite infections or molecules seem to display protective effects on some cancers, such as is the case with Echinococcus. [2]

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]

The protective role of helminths

Helminths may be able to elicit anti-tumor immune responses that can lead to protection from tumorigenesis, or even to cancer regression.

• The bifacial role of helminths in cancer: involvement of immune and non-immune mechanisms

Helminth infection may limit the growth and dispersion of tumors.

• The immune response to Hymenolepis nana in mice decreases tumorigenesis induced by 7,12 dimethylbenz-anthracene

Helminth infection may reduce the risk of colitis-associated tumour formation.

• Helminth-derived molecules inhibit colitis-associated colon cancer development through NF-kB and STAT3 regulation

• Extraintestinal helminth infection reduces the development of colitis-associated tumorigenesis

• Gastrointestinal Nematode-Derived Antigens Alter Colorectal Cancer Cell Proliferation and Migration through Regulation of Cell Cycle and Epithelial-Mesenchymal Transition Proteins

Helminth infection may alter inflammatory responses to H. pylori and thus affect the progression of gastritis to gastric atrophy, dysplasia, and cancer.

• Intestinal helminthiasis in Colombian children promotes a Th2 response to Helicobacter pylori: possible implications for gastric carcinogenesis

The high prevalence of helminth infections in Sub-Saharan Africa may be responsible for a reduced risk of gastric adenocarcinoma.

• The impact of Helicobacter pylori and intestinal helminth infections on gastric adenocarcinoma and inflammatory bowel disease in Sub-Saharan Africa -- Full text | PDF

Cancer has been linked to inflammation, which is controlled by helminths

• Chronic Inflammation Linked to High-Grade Prostate Cancer

• Pre-existing inflammation (from allergic reactions) may promote the spread of cancer

• Preoperative management of inflammation may stave off cancer recurrences

Helminths and their products may potentially treat cancer

Helminths exert antitumor effects via several mechanisms of action.

The beneficial effects reported for some parasitic diseases on tumorigenesis range from the induction of apoptosis, activation of the immune response, avoiding metastasis and angiogenesis, inhibition of proliferative signals, to the regulation of inflammatory responses that promote cancer. [6]

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

Originally my doctor wanted to try these guys (NA) as an experiment to see if they help with reducing my cancer. We also found out these guys help the genetic condition that caused my cancer (FAP) which mimics an autoimmune disease. There are few studies that prove that elevated eosinophils actually help kill colorectal cancer cells. Six months into it, I'm cancer free. [7]

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.

• Anti-Tumor Effect of Marshallagia marshalli Somatic Antigen on Inhibition Cell Growth of K562 -- Full text | PDF

• Immunomodulatory action of excretory-secretory products of Angiostrongylus cantonensis in a mouse tumour model

• Helminth-induced apoptosis: a silent strategy for immunosuppression.

• Hookworm exposure decreases human papillomavirus uptake and cervical cancer cell migration through systemic regulation of epithelial-mesenchymal transition marker expression -- Full text | PDF

• The helminth-derived peptide GK-1 induces an anti-tumoral CD8 T cell response associated with downregulation of the PD-1/PD-L1 pathway

Infection with other microorganisms may also help to reduce cancer risk

Researchers found that enhanced biodiversity (of bacteria and worms) was associated with better immune responsiveness. Specifically, they found better responses to vaccination, better T-cell responses, and much higher levels of "natural" antibodies, which have been shown to be important in fighting cancer. [9]

BCG vaccination in infancy confers a survival advantage for melanoma patients, and vaccination of adults against yellow fever may have a similar effect.

• The biography of the immune system and the control of cancer: from St Peregrine to contemporary vaccination strategies

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.

• Does cat poop parasite play a role in curing cancer?

Rather than the presence of infectious microorganisms increasing cancer risk, a lack of them may be the greater problem.

…attenuated responses to tumor antigens as a result of biome depletion might underlie, at least in part, the proposed connection between increased rates of cancer and biome depletion. Further, decreased levels of “natural” IgG and IgM observed in biome depleted (laboratory) environments could exacerbate the problem, since the natural antibody repertoire is involved in tumor surveillance. In this manner, decreased tumor surveillance in biome depleted environments could promote cancer progression and operate synergistically with biome depletion-associated inflammation, a potential initiator and promoter of carcinogenesis. [10]

Anthelmintic drugs may be used in cancer treatment

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

This rare case in which a man died after a tapeworm inside him developed cancer, involved a helminth that is not used in therapy.

• Malignant Transformation of Hymenolepis nana in a Human Host -- Full text

For a discussion about this case, see this support group thread.

See also

• Helminthic therapy safety