Skin Bacteria’s Protective Benefits Against Skin Cancer

Our bodies contain approximately 30 trillion human cells and, recent research estimates, an equal number, 30 trillion, of beneficial bacteria. Called bacterial flora, microbiota or microbiome , these bacteria live with us in a mutually beneficial relationship (commensalism), have many health roles and occur across the skin and intestines. Though numerous, their cells are small: a person weighing 70 kilos has 1.5 kilograms of bacteria. Studies have linked flora to colorectal and skin cancers and immune responses to cancer. Many also call microbiota the 2nd brain and link it to psychological/psychiatric states, but evidence here is weak.

- Related topic: What is intestinal flora (microbiota/microbiome)? How is it related to colorectal cancer?

Science Advances published a University of California San Diego School of Medicine study reporting a new beneficial role of some skin bacteria: protection against skin cancer.

In a mouse study, a skin flora bacterium called Staphylococcus epidermidis produced a chemical killing cancer cells but not toxic to normal cells: 6-N-hydroxyaminopurine (6-HAP). Mice were divided into two groups exposed to high-dose carcinogenic ultraviolet (UV) radiation. Those with S. epidermidis producing no 6-HAP developed many skin tumors after UV exposure; those with 6-HAP-producing S. epidermidis developed none.

Many functions of the 6-HAP molecule were identified; disrupting DNA formation (DNA synthesis), preventing cancerous tumor cell spread and suppressing UV-induced skin tumors.

Skin cancers fall broadly into two groups: less common malignant melanoma (5%) and nonmelanoma cancers (95%). Skin cancers are the most common cancers worldwide, and many are treated with uncomplicated procedures requiring no chemotherapy. More than 95% are caused by excessive UV exposure.

Evidence increasingly establishes the skin microbiome's contribution to health. Earlier studies showed some skin bacteria produce peptides against harmful/pathogenic bacteria.

To understand protection or risk reduction, we first need to understand how 6-HAP forms. Further studies may help identify effective skin cancer prevention approaches.

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- A new option against basal and squamous cell skin cancers: Vitamin B3

- Intestinal flora diversity may increase immunotherapy effectiveness

- What are probiotics? Is yogurt beneficial for colon cancer prevention and intestinal microbiota?

- A new option against basal and squamous cell skin cancers: Vitamin B3