David Paul von Hansemann
Biography of David Paul von Hansemann
David Paul von Hansemann first embarked on a career as a merchant, but changed his course to study medicine in Berlin, Kiel, and Leipzig, particularly under Wilhelm His (1931-1904), Carl Friedrich Wilhelm Ludwig (1816-1895), Ernst Leberecht Wagner (1829-1888), and Julius Cohnheim (1839-1884).
Hansemann defended his doctoral dissertation in 1886 under Julius Cohnheim. For the next nine years he was an assistant to Rudolf Ludwig Karl Virchow (1821-1902) at the University of Berlin. He
He was habilitated for pathological anatomy in 1890, becoming titular professor of anatomy and pathology in 1897. In 1907 he also became prosector at the city hospital Friedrichshain. From 1906 prosector at the Rudolf Virchow Hospital. He became ordinary honorary professor in 1912. Hansemann was an army pathologist in World War I.
Hansemann had a special interest in cancer and, in 1890, only a few years after the discovery of the chromosome, he described the concept of anaplasia. This theory postulates that the increased growth potential of the cancer cell was accompanied by a loss of differentiation and that asymmetrical mitoses were a characteristic of cancer. Hansemann contrasted his theory of anaplasia to the more popular theory of embryonalism; embryonal tissues remained undifferentiated, while anaplastic tissues had once been differentiated.
The term anaplasia is from the Greek, ana, backward + plassein, to form, or forming backward.