People with tattoos bigger than the palm of their hand had more than double the risk of skin cancer and lymphoma, a cancer of the immune system, in a Danish twin study. The lymphoma number that went viral rests on 32 cancer cases, and only 7 of them had tattoos. Researchers at the University of Southern Denmark used the Danish Twin Registry for two studies. One followed 2,367 randomly chosen twins. The other looked at 316 twins born between 1960 and 1996, from pairs where at least one twin got cancer. Cancer diagnoses came from national records, tattoo details came from a 2021 survey, and BMC Public Health published the results in 2025. Ink from a tattoo travels from the skin into the blood and builds up in nearby lymph nodes, the small immune filters in places like your armpits and neck. The researchers worry the ink causes long-lasting inflammation there. Over years, that could push cells to grow out of control. Tattooed people in the second study had a 62 percent higher risk of skin cancer. For tattoos larger than a palm, skin cancer risk was 2.4 times higher and lymphoma risk was 2.7 times higher. In the group of 2,367 twins, tattooed people had about 4 times the risk of skin cancer. Once tattoo size was ignored, tattoos showed no clear link to lymphoma. Comparing each tattooed twin with their own untattooed sibling, the strongest test a twin study can run, wasn't possible for lymphoma because there were too few pairs. For skin cancer, that twin-versus-twin test used just 14 pairs and found a much smaller link that could easily be chance. Sun exposure wasn't measured either, and the authors note that tattoos can make skin cancers harder to spot. The concern about ink is serious enough to study further. The headline lymphoma risk, though, comes from 7 tattooed patients.