Abstract: This invention relates to proteins or peptides that elicit T cell mediated immunity, and to cancer vaccines and compositions for anti-cancer treatment comprising such proteins or peptide fragments. This invention also relates to pharmaceutical compositions comprising the proteins or peptides and methods for generating T lymphocytes capable of recognizing and destroying tumor cells in a mammal. More specifically, a telomerase protein or peptide for use in a method of treatment or prophylaxis of cancer is provided. In a preferred embodiment, the method comprises generating a T cell response against telomerase.