Ivermectin, Mebendazole and Colon Polyps: Could PAK1 Inhibition Explain a Surprising Colonoscopy Result?

A recent viral post by William Makis sparked widespread discussion in the cancer and repurposed-drug community after a Florida physician in his 70s reportedly experienced his first completely polyp-free colonoscopy in 25 years while taking ivermectin and mebendazole for Stage 3 prostate cancer.

The story quickly gained traction because it touched on a growing scientific topic: the role of PAK1 signaling in colon polyps, colorectal cancer, and abnormal cellular growth.

While the case is anecdotal and does not prove causation, the underlying biology is more interesting than many critics realize. Research over the past 15 years has linked PAK1 (p21-activated kinase 1) to colorectal adenomas, Wnt/β-catenin signaling, cancer cell proliferation, and tumor progression. Multiple preclinical studies have also shown that ivermectin can inhibit PAK1 activity.

Could this help explain the unexpected colonoscopy result?

Here’s what the science actually says.

What Happened in the Viral Colonoscopy Story?

According to the testimonial shared online:

• A physician in his 70s had a long history of recurrent colon polyps during routine colonoscopies over roughly 25 years.

• He later began taking ivermectin and mebendazole as part of a broader protocol for Stage 3 prostate cancer.

• After approximately 10 months on the regimen, his next colonoscopy reportedly showed zero polyps for the first time in decades.

The post did not claim proof of cure or prevention. Instead, it proposed a biologically plausible explanation involving PAK1 inhibition.

That distinction matters.

A single anecdote cannot establish effectiveness. However, when a surprising clinical observation aligns with known molecular pathways, it can generate important scientific hypotheses worth investigating further.

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What Is PAK1?

PAK1 stands for p21-activated kinase 1, a signaling protein involved in:

• Cell proliferation

• Cytoskeletal remodeling

• Cell survival

• Migration and invasion

• Inflammatory signaling

• Cancer progression

PAK1 has been implicated in multiple cancers, including:

• Colorectal cancer

• Prostate cancer

• Breast cancer

• Pancreatic cancer

• Lung cancer

• Melanoma

In colorectal biology specifically, PAK1 appears closely linked to the adenoma-carcinoma sequence — the progression from benign colon polyps to colorectal cancer.

PAK1 and Colon Polyps

Research has shown that PAK1 expression tends to increase as colorectal adenomas enlarge and become more dysplastic.

PAK1 also interacts with major cancer pathways including:

• Wnt/β-catenin

• AKT/mTOR

• MAPK

• NF-κB

These pathways help drive:

• abnormal cell proliferation,

• resistance to apoptosis,

• stem-cell signaling,

• and tumor growth.

In APCmin/+ mouse models — one of the classic preclinical models of intestinal adenoma formation — reducing PAK1 activity significantly decreased polyp burden.

That is one reason scientists have explored PAK1 as a potential anti-cancer and anti-polyp target.

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How Does Ivermectin Affect PAK1?

Ivermectin was originally developed as an antiparasitic drug, but researchers later discovered it has several unexpected effects on cancer-related signaling pathways.

One of the most studied is PAK1 inhibition.

Preclinical studies suggest ivermectin may:

• Inactivate PAK1 signaling

• Promote PAK1 ubiquitination and degradation

• Suppress AKT/mTOR activity

• Trigger cytostatic autophagy

• Increase apoptosis in cancer cells

• Reduce proliferation in tumor models

Several laboratory studies involving colorectal cancer cells have shown that ivermectin can:

• inhibit cell growth,

• induce oxidative stress,

• arrest the cell cycle,

• and promote programmed cell death.

These findings remain preclinical, meaning they were observed in cells or animal models — not confirmed in large human trials.

Still, the mechanistic overlap with colorectal adenoma biology is scientifically plausible.

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Where Does Mebendazole Fit In?

Mebendazole may also play an important role.

Although mebendazole is better known for disrupting microtubules in parasites, researchers have explored additional anti-cancer effects such as:

• Wnt/β-catenin modulation

• Angiogenesis inhibition

• MYC suppression

• Metabolic stress induction

• Cancer stem-cell targeting

• Cell-cycle disruption

Unlike ivermectin, mebendazole is not primarily associated with PAK1 inhibition.

However, the two drugs may theoretically produce overlapping anti-proliferative effects through different pathways.

That means the reported colonoscopy outcome — if genuinely drug-related — could reflect combination effects rather than ivermectin alone.

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Why This Colonoscopy Result Is Scientifically Interesting

A patient with:

• decades of recurrent polyps,

• regular surveillance colonoscopies,

• and then a sudden completely polyp-free examination

represents an unusual clinical pattern.

That does not prove the drugs caused the change.

Other possible contributors could include:

• diet changes,

• weight loss,

• supplements,

• altered inflammation,

• improved metabolic health,

• or natural variability.

However, the observation becomes more compelling because:

1. PAK1 is strongly linked to adenoma formation.

2. Ivermectin appears capable of suppressing PAK1 signaling.

3. The clinical observation aligns with the proposed mechanism.

This is what scientists call biological plausibility.

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Could Ivermectin Prevent Colon Polyps?

At present, there is no clinical proof that ivermectin prevents colon polyps in humans.

No large randomized controlled trials have demonstrated:

• reduced adenoma recurrence,

• improved colorectal cancer prevention,

• or long-term chemopreventive benefits.

That is an important limitation.

Still, the concept deserves attention because preventing adenomas may be biologically easier than treating advanced cancer.

Colon polyps are:

• earlier lesions,

• less genetically unstable,

• and often more dependent on growth signaling pathways.

Many successful colorectal cancer prevention strategies began with mechanistic observations long before definitive trials were completed.

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What the Current Evidence Actually Supports

The current evidence supports several conclusions:

Supported by Preclinical Research

• PAK1 contributes to colorectal adenoma growth.

• Ivermectin can inhibit PAK1 signaling.

• Ivermectin demonstrates anti-proliferative effects in colorectal cancer models.

• Mebendazole also has multiple anti-cancer mechanisms.

Not Yet Proven in Humans

• Ivermectin prevents colon polyps.

• Ivermectin reverses adenomas clinically.

• Ivermectin reduces colorectal cancer risk.

• Ivermectin plus mebendazole is an established anti-polyp therapy.

That distinction is essential for interpreting viral testimonials responsibly.

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Why Repurposed Drugs Are Getting Attention in Oncology

Repurposed drugs such as:

• ivermectin,

• mebendazole,

• fenbendazole,

• metformin,

• and statins

have attracted interest because they are:

• inexpensive,

• widely available,

• and already have known safety data.

Researchers are increasingly exploring whether some older drugs may influence:

• metabolism,

• inflammation,

• immune signaling,

• cancer stem cells,

• or tumor microenvironments.

However, promising mechanisms do not automatically translate into effective human treatments.

Cancer biology is complex, and many therapies that look exciting in laboratory studies ultimately fail in clinical trials.

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Final Thoughts

The viral colonoscopy story involving ivermectin and mebendazole is intriguing because it combines:

• a striking anecdotal observation,

• a plausible biological mechanism,

• and established preclinical research involving PAK1 signaling.

At the same time, it remains a single uncontrolled testimonial.

The science behind PAK1 inhibition is legitimate and increasingly studied in oncology. Whether that ultimately translates into meaningful prevention or treatment benefits for colon polyps in humans remains unknown.

For now, the case should be viewed as:

• a hypothesis-generating clinical observation,

• not proof of efficacy.

Still, it highlights why researchers continue exploring repurposed drugs in cancer biology — especially when unexpected real-world outcomes align with known molecular pathways.

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Frequently Asked Questions

What is PAK1?

PAK1 (p21-activated kinase 1) is a signaling protein involved in cell growth, survival, and cancer progression. It is overexpressed in several cancers and colorectal adenomas.

Does ivermectin inhibit PAK1?

Preclinical studies suggest ivermectin can inhibit PAK1 signaling and promote degradation of the protein in certain cancer models.

Can ivermectin remove colon polyps?

There is currently no clinical evidence proving ivermectin removes or prevents colon polyps in humans.

Is mebendazole used for cancer?

Mebendazole is not an approved cancer treatment, but researchers have investigated its potential anti-cancer properties in laboratory and animal studies.

Are there clinical trials for ivermectin and cancer?

Some early-stage and exploratory studies exist, but there are currently no large definitive clinical trials proving ivermectin is an effective cancer therapy.