Thursday, Sep 10, 2026 The claims desk. Receipts included. POWERED BY LENZ ↗
IsThis

Medical and scientific studies have documented cancerous tumors in sharks.

The Claim

Sharks do not get cancer.

Verified by Lenz ·

The Short Version

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.

Caveats

  • The claim uses absolute wording; documented cancer cases in sharks are enough to disprove it.
  • Evidence about low mutation rates, cartilage, or cancer-related genes does not logically imply zero cancer incidence.
  • Cancer in wild sharks may be underdetected, but uncertainty about prevalence is not evidence that sharks do not get cancer.

The Receipts

  1. Cartilage (Bovine and Shark) (PDQ®)–Health Professional Version

    National Cancer Institute

  2. Shark cartilage, cancer and the growing threat of pseudoscience

    PubMed - Cancer Research

  3. Low mutation rate in epaulette sharks is consistent with a slow-evolving lineage

    PubMed

  4. Sharks do get cancer: few surprises in cartilage research

    PubMed (National Center for Biotechnology Information)

  5. Retrospective Study of the Prevalence, Histopathology, Therapy, and Outcomes of Neoplasia in Pet Fish

    PMC - NIH

  6. Industrial application of fish cartilaginous tissues

    PMC - NIH

  7. Long-term Observation of Cancer in a Shark

    The Shark Trust (sharks.org)

  8. Sharks show novel evolution of immune, cancer-related genes

    Cornell University News

  9. Fighting metastatic cancer with the help of sharks

    UW Health (University of Wisconsin)

  10. Jaws Never Dies: Sharks Don't Get Cancer

    Chapman University

+ 3 more sources — see the full list on Lenz

Filed Under

cancersharks

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