(8) Most of the cantons have adopted legislation on data protection for the areas for which they are competent, in particular public hospitals, education, direct cantonal taxes and the police. In the remaining cantons, such data processing is governed by regulatory acts or by the principles of cantonal case-law. Whatever the source and content of the cantonal provisions, or even if no cantonal provisions exist, cantons must adhere to the constitutional principles. In their field of responsibility, the cantonal authorities may have to transfer personal data to public authorities in neighbouring countries, mainly for the purpose of mutual assistance to safeguard important public interests or, in the case of public hospitals, to protect the vital interest of the persons concerned.