Library.

“Magnetic resonance imaging (MRI) scans cause cancer.”

Available evidence does not support MRI scans as a cause of cancer. Unlike X-rays and CT scans, MRI uses non-ionizing magnetic and radiofrequency fields rather than DNA-damaging ionizing radiation, and no cancer increase from ordinary clinical MRI has been established. MRI has other recognized safety considerations, but they do not substantiate this cancer claim.

“Eating smoked foods increases the risk of cancer in humans.”

The evidence supports a real increase in cancer risk, especially for processed and heavily smoked meats. High-quality sources, including IARC/WHO and major cancer agencies, link smoke-derived carcinogens such as PAHs and certain smoked/processed meats to higher cancer risk in humans. The claim is somewhat overbroad because risk is not equally established for every smoked food, and it depends on dose and preparation.

“Fever can sometimes cure cancer.”

Rare cancer regressions have been reported after high fevers, acute infections, or fever-inducing treatments, so the idea has some factual basis. But the evidence mostly consists of case reports, historical series, and correlations, not proof that fever itself directly cures cancer. In modern medicine, hyperthermia is used as an adjunct to other treatments, not as a reliable stand-alone cure.

“Artificial intelligence systems are used in clinical practice to assist with medical imaging diagnosis, such as detecting cancers on radiology images.”

AI tools are already used in real clinical radiology settings to help detect or assess findings on medical images, including some cancer-related applications. The strongest evidence comes from government, peer-reviewed, and specialty-society sources describing FDA-cleared systems used as decision-support or second-reader tools. The main caveat is that use is uneven and these systems usually assist clinicians rather than diagnose on their own.

“Sharks do not get cancer.”

Sharks are not cancer-proof. Authoritative medical sources and peer-reviewed studies document both benign and malignant tumors in sharks and explicitly identify the claim as a myth. Research on low mutation rates or distinctive immune genes may suggest biological differences, but it does not show that sharks never develop cancer.

“In Mexico, cancer accounts for approximately 14% of annual deaths.”

The 14% figure has some support in international modeled estimates, but Mexico’s direct national death registry data more often put cancer closer to about 12% of annual deaths. That gap is large enough to matter for a reader’s understanding. The statement therefore blends two different data approaches and overstates the share shown in recent registered deaths.

“For a non-pregnant adult, drinking one standard glass of red wine per day increases cancer risk compared with drinking no alcohol.”

Available evidence indicates that one daily glass of red wine raises the risk of certain cancers compared with not drinking alcohol, because the carcinogenic agent is ethanol, not the beverage type. Major cancer and public-health agencies state that risk begins at low levels of intake. The main caveat is that wine-specific studies on overall cancer are mixed, and the increase at one drink per day is small in absolute terms and varies by cancer type and sex.

“Alcohol consumption causes cancer in humans.”

Alcohol is a well-established human carcinogen. Major public-health and cancer authorities state that drinking alcohol causally increases the risk of several cancers, including breast, colorectal, liver, esophageal, and head-and-neck cancers. The claim is broad, but the omitted nuance does not alter the central fact that alcohol consumption causes cancer in humans.

“Obesity is a causal risk factor for developing cancer in humans.”

Evidence from major health agencies, large cohort meta-analyses, mechanistic experiments, and weight-loss interventions consistently shows that excess body fat contributes to the development of multiple common cancers in humans. While strength of evidence varies by cancer site and some trials of modest lifestyle weight loss are inconclusive, the overall scientific consensus classifies obesity as a causal risk factor for cancer rather than a mere correlation.

“Vitamin C has a negative effect on cancer outcomes.”

The weight of high-quality evidence contradicts this claim. Multiple meta-analyses, umbrella reviews, and clinical studies associate vitamin C with reduced cancer incidence and improved prognosis — not worsened outcomes. The narrow concern about vitamin C interfering with certain chemotherapy drugs has been observed primarily in preclinical and animal studies, not consistently in human trials. The only controlled clinical trial in the evidence base found no harm from high-dose vitamin C, only no benefit — which is not a "negative effect."

“Vaping causes cancer in humans.”

Current evidence does not support the definitive claim that vaping causes cancer in humans. Human studies showing elevated cancer risk involve dual users who also smoke combustible cigarettes — a known carcinogen — making it impossible to isolate vaping as the independent cause. Multiple systematic reviews find no significant cancer risk in exclusive never-smoker vapers. While biomarker evidence of DNA damage and a recent review calling vaping "likely" carcinogenic suggest biological plausibility, no authoritative body has confirmed a definitive causal link for vaping alone.

“A declassified Central Intelligence Agency document reveals the existence of a cancer cure that has been suppressed.”

The declassified memo discusses 1950 Soviet lab work; it does not document a proven cancer cure, nor was it hidden—files have been publicly available for years. No credible evidence supports a suppressed, definitive cure.