Provided herein are genetically modified arenaviruses suitable as vaccines against neoplastic diseases or cancer. The invention also relates to pharmaceutical compositions and methods for the prevention or treatment of certain infections causing neoplastic diseases or cancer, such as infections with oncogenic viruses. Specifically, provided herein are pharmaceutical compositions, vaccines, and methods of preventing or treating diseases and conditions caused by and associated with infections with Human Papillomavirus (HPV), such as cervical cancer, anogenital cancer, head and neck cancer and skin cancers. Also provided herein are immunotherapies for the treatment of a neoplastic disease, such as a neoplastic disease caused by infection with oncogenic viruses.