This year, an estimated 100,000 people in the U.S. will be diagnosed with melanoma, a rare but aggressive form of skin cancer — and even if they beat it, they’ll be at a high risk of developing melanoma again.

That might not always be the case, though, as a personalized skin cancer vaccine developed from patients’ own tumor cells has shown promise in a very small trial, involving eight melanoma survivors.

“We found evidence of everything we look for in a strong, sustained immune response,” study co-leader Patrick A. Ott said in a press release.