<human>:  Did Jack Dempsey have most title fight wins in either of his weight classes?
<bot>: No, Jack Dempsey was an American boxer. He did not have the most title fight wins in either of his weight classes. Jack Dempsey competed as a heavyweight and a lightheavyweight. Jack Dempsey only had a handful of title defenses as heavyweight champion. Wladimir Klitschko had 25 heavyweight title fight wins.