Elevated Cathelicidin and Beta-Defensin 2 Blood Levels May Signal Basal Cell Skin Cancer | Research

The takeaway

Patients with basal cell carcinoma had cathelicidin levels 3x higher and beta-defensin 2 levels 6x higher than controls, with elevated cathelicidin conferring a 9.9x higher likelihood of BCC diagnosis.

9.9x higher BCC likelihood
Patients with cathelicidin above ~1,500 pg/mL were 9.9 times more likely to have basal cell carcinoma than those below this threshold

What the researchers found

Cathelicidin was ~3x and HBD-2 was >6x higher in BCC patients (p<0.001). Cathelicidin >1,500 pg/mL: OR 9.9 for BCC. HBD-2 >1.2 ng/mL: OR 12.6 for BCC (p<0.001). Both showed high specificity for detecting BCC.

Why it matters

A simple blood test measuring antimicrobial peptide levels could potentially help detect basal cell carcinoma — the world's most common cancer — complementing visual skin examination, especially for lesions that are difficult to assess clinically.

The numbers in context

Cathelicidin ~3x higher; HBD-2 ~6x higher; cathelicidin >1500 pg/mL: OR 9.9; HBD-2 >1.2 ng/mL: OR 12.6 (p<0.001); high specificity

How the study worked

Case-control study. 49 BCC patients and 59 controls. Serum cathelicidin and HBD-1, HBD-2, HBD-3 measured. Logistic regression for diagnostic accuracy. Statistical analysis of group differences.

Who was studied

Patients with basal cell carcinoma and age-matched controls

What this study cannot tell us

Relatively small case-control study. Cathelicidin and defensins are elevated in many conditions (infections, inflammation), limiting specificity for BCC specifically. Cannot determine whether elevated AMPs are a cause or consequence of BCC. No longitudinal data.

How to read the evidence

Moderate evidence: case-control study with strong statistical results and clinically meaningful odds ratios, but small sample and cross-sectional design limit conclusions.

When this study was published

Published 2021. Research on antimicrobial peptides as cancer biomarkers continues with larger validation studies needed.

The bigger picture

AMPs are increasingly recognized not just as infection fighters but as markers of various diseases including cancer. Finding that cathelicidin and defensins are elevated in BCC connects innate immunity to skin carcinogenesis and could eventually lead to non-invasive cancer screening tools.

Questions still open

Do antimicrobial peptide levels correlate with BCC stage, size, or subtype?
Could serial monitoring of cathelicidin/HBD-2 detect BCC recurrence after treatment?
Do these elevated peptides promote or inhibit BCC growth?

Common questions

Could a blood test detect skin cancer?

This study suggests it might be possible. Patients with basal cell carcinoma had dramatically higher blood levels of two antimicrobial peptides — cathelicidin and beta-defensin 2. If validated, measuring these peptides could complement visual skin examinations for cancer detection.

Why are antimicrobial peptides elevated in skin cancer?

The exact reason isn't clear. Antimicrobial peptides may be produced by the immune system in response to the tumor, or the cancer cells themselves may trigger AMP production. Whether elevated AMPs help fight or promote the cancer requires further investigation.

Read the original research

Elevated serum levels of cathelicidin and β-defensin 2 are associated with basal cell carcinoma.

Central-European journal of immunology, 46(3), 360-364

View on PubMed ↗Publisher’s paper ↗

Citation

Fijałkowska, Marta; Kowalski, Marek; Koziej, Mateusz; Antoszewski, Bogusław. (2021). Elevated serum levels of cathelicidin and β-defensin 2 are associated with basal cell carcinoma.. Central-European journal of immunology, 46(3), 360-364. https://doi.org/10.5114/ceji.2021.109707