*2.1. Ethics*

Human tumors were obtained from the Institute of Pathology, University Hospital Salzburg. The study was performed according to the Austrian Gene Technology Act. Experiments were conducted in accordance with the Helsinki Declaration of 1975 (revised 2013) and the guidelines of the local ethics committee, being no clinical drug trial or epidemiological investigation. All patients signed an informed consent document concerning the surgical intervention. Furthermore, the study did not extend to the examination of individual case records. Patient anonymity was ensured at all times. All analyses on human CCC samples were approved by the local ethics committee (415-EP/73/37-2011).
