35 On the Origin of Cancer Cells* 

 By Otto Warburg 



Our principal experimental object for the measurement of the metabolism of Cancer 

 cells is today no longer the tumor but the ascites Cancer cells l living free in the 

 abdominal cavity, which are almost pure cultures of Cancer cells with which one 

 can work quantitatively as in chemical analysis. Formerly, it could be said of tumors, 

 with their varying Cancer cell content, that they ferment more strongly the more 

 Cancer cells they contain, but today we can determine the absolute fermentation 

 values of the Cancer cells and find such high values that we come very close to the 

 fermentation values of wildly proliferating Torula yeasts. 



What was formerly only qualitative has now become quantitative. What was 

 formerly only probable has now become certain. The era in which the fermentation 

 of the Cancer cells or its importance could be disputed is over, and no one today 

 can doubt that we understand the origin of Cancer cells if we know how their large 

 fermentation originates, or, to express it more fully, if we know how the damaged 

 respiration and the excessive fermentation of the Cancer cells originate. 



Energy of Respiration and Fermentation 



We now understand the chemical mechanism of respiration and fermentation 

 almost completely, but we do not need this knowledge for what follows, since 

 energy ahne will be the center of our considerations. We need to know no more of 

 respiration and fermentation here than that they are energy-producing reactions 

 and that they synthesize the energy-rich adenosine triphosphate, through which 

 the energy of respiration and fermentation is then made available for life. Since 

 it is known how much adenosine triphosphate can be synthesized by respiration and 

 how much by fermentation, we can write immediately the potential, biologically 

 utilizable energy production of any cells if we have measured their respiration and 

 fermentation. With the ascites cancer cells of the mouse, for example, we find an 

 average respiration of 7 cubic millimeters of oxygen consumed per milligram, per 



* Reprinted from Science 123 (1956): 309 by permission. 



Zusatz 1961. Der in diesem Vortrag beschriebene Fortschritt ist der Über- 

 gang von den Tumoren, die alle Mischgewebe sind, zu den freien Krebszellen : zu 

 den Ascites-Krebszellen und zu den in vitro gezüchteten Krebszellen der Earle- 

 schen Schüttelkulturen, deren Untersuchung Dean Burk in einem Addendum 

 beschreibt. Im übrigen aber sind viele Ideen des Vortrags heute als überholt zu 

 betrachten, zum Beispiel die Entstehung des Krebsstoffwechsels durch Selektion, 

 die Wirkungsweise der Röntgenstrahlen bei der Abtötung der Krebszellen und 

 auch die Verminderung der Zellgrana als Ursache der zu niedrigen Atmung der 

 Krebszellen. Trotzdem habe ich den Vortrag in unsere Sammlung aufgenommen, 

 um zu zeigen, in wie schneller Entwicklung die hier diskutierten Probleme heute 

 begriffen sind. 



