Skin Microbiome Shifts Signal Squamous Cell Carcinoma Risk

Emerging evidence shows fungal and viral skin microbes may help identify high-risk patients before cancer develops

Researchers have discovered distinct skin microbiome changes including increased levels of certain fungi and viruses in individuals at high risk for cutaneous squamous cell carcinoma (SCC). These findings suggest that microbiome analysis could one day help detect cancer risk earlier, particularly in older adults and immunosuppressed patients.

Study Details

The study, led by investigators from Massachusetts General Hospital and the National Institutes of Health, explored whether changes in the skin’s microbial ecosystem could distinguish people with high SCC risk from those at low risk. While SCC is one of the most common skin cancers, current risk assessments rely largely on whether a patient has already developed multiple tumors. The goal was to see if microbial signatures could serve as an early warning system, enabling preventive care before repeated cancers occur.

Methodology

Researchers collected skin swabs from 30 participants, including six with a history of frequent SCCs, nine with low SCC risk, and fifteen solid organ transplant recipients, who face increased cancer risk due to immunosuppressive therapy. Samples were taken from six different skin sites and analyzed using shotgun metagenomic sequencing to map the composition of the skin microbiome.

Key Findings

Both high-risk SCC patients and transplant recipients showed significantly greater abundance of two fungal species Malassezia restricta and Malassezia globosa as well as Betapapillomaviruses, compared with low-risk individuals.

These microbial patterns were distinct enough to differentiate between high- and low-risk groups, even in the absence of visible fungal conditions. While it remains unclear whether these microbes directly contribute to cancer development or simply reflect immune system changes, their consistent presence in high-risk groups points to potential value as early biomarkers.

Implications for Practice

If confirmed in larger studies, skin microbiome profiling could provide a noninvasive tool to identify patients at increased risk for SCC before the disease becomes recurrent. This may be especially valuable for older adults experiencing immune system decline and for transplant recipients. Dermatologists may eventually incorporate microbiome analysis into routine skin cancer screening, though current evidence does not support trying to alter the microbiome through supplements or topical agents as a prevention method.

Researchers are working on simpler, more affordable ways to detect these microbial shifts, with the aim of making this form of screening widely available in the coming years.