We are not aware of a reported cancer case directly attributable to tattooing. However, evidence does show that some tattoo inks contain carcinogens (cancer-causing substances) – chemicals that have been classified as known or possible carcinogens by the WHO’s International Agency for Research on Cancer. Subsequently, a 2016 report from the Australian Government’s Department of Health, National Industrial Chemical’s Notification and Assessment Scheme (NICNAS), looked into the composition of 49 tattoo inks and found a mismatch between content and labelling, as well as concern about some components. Polycyclic Aromatic Hydrocarbons (PAHs), a group of chemicals which are known carcinogens, was found in a fifth of the samples tested and in 83% of the black inks tested by NICNAS. Other hazardous components included barium, copper, mercury, amines and various colourants. In order to achieve the permanent effect, tattoo ink is injected into the dermis – the deeper layer of the skin – and stays in the skin for a lifetime. Over time, macrophages take up pigment and may transport in into the lymphatic system and lymph nodes. This means other tissue in the body can be exposed to potentially carcinogenic materials in the tattoo ink. A recent review found that the number of skin cancers in tattooed skin was low, and therefore seems coincidental, however a number of carcinogens that have been found in tattoo inks have been associated with cancers elsewhere in the body, such as the liver or bladder. If a tattoo covers or surrounds a mole you might not see changes that could indicate skin cancer, and the tattoo pigments in your skin may make it difficult for a doctor to accurately detect cancer, delaying diagnosis of melanoma or skin cancer. If you are concerned, don’t get tattooed. Or if you choose to get tattooed, ask if the inks being used comply with the European standard known as ResAP(2008)1, which sets out the requirements and criteria for the safety of tattoos.