ssh use known_hosts other than $HOME/.ssh/known_hosts

Is it possible to run SSH using another `known_hosts` file than the standard `$HOME/.ssh/known_hosts` for the user? Note, that SSH uses `$HOME` original for the user. If you try to change it, e.g. <!-- language: shell --> export HOME=some_other_location it does not affect the location SSH uses to look for `known_hosts`.