Chemical components of tattoo inks and their potential role in carcinogenesis and their side effects

Tattooing is an invasive procedure that has gained popularity, particularly among individuals. Growing attention has been directed toward the safety of tattoo ink ingredients, which are complex mixtures of synthesis precursors and byproducts. These inks may contain classified carcinogens, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and phthalates, often at concentrations exceeding permissible limits. Tattooing involves the insertion of needles 1-3 mm into the dermis. While part of the pigment is eliminated with epidermal turnover, approximately 25% is transported to lymph nodes and subsequently into the bloodstream. The remaining pigment is engulfed by phagocytic cells involved in innate immunity. Repeated needle punctures trigger local inflammation, recruitment of immune cells, and release of inflammatory mediators, followed by tissue regeneration and remodelling driven by keratinocytes, fibroblasts, and endothelial cells. Cases of malignant melanoma, squamous cell carcinoma, keratoacanthoma, and lymphoma have been reported in individuals with tattoos. However, the relationship between tattooing and cancer is not fully understood. It is suspected that the cause may be the transfer of toxic substances to lymph nodes and then to organs. The possible carcinogenic effects of tattoo ink ingredients will be discussed based on available scientific reports.