HAROLD P. RUSCH 



Such a cell has lost its major potential for specialized function 

 and is doomed to a continuous process of reduplication. It 

 represents a reversion to a unicellular type of life. This ad- 

 vanced stage seldom if ever occurs in an animal bearing a 

 spontaneous or induced cancer, because the host does not live 

 sufficiently long to permit a complete regression, but such neo- 

 plastic cells are illustrated by certain types of ascites tumor cells 

 derived from tumors which have undergone repeated transfer. 

 The tendency for unicellularity is evident to some degree in all 

 neoplasms which tend to form abnormal architectural patterns 

 and which give rise to cells which metastasize. 



On the basis of the discussion just presented, the conclusions 

 reached by the committee in 1938 may be extended with the 

 following ideas : 



7. Carcinogens induce a change in one or more of the 

 special functions of the cell. The resulting change is heritable. 



2. An untimely alteration of function disrupts the normal 

 sequence of differentiation and the resulting metabolic patterns. 

 In such cells, the pattern for reduplication is retained and 

 predominates to varying degrees. 



3. Cells which have suffered from such heritable change 

 may require the additional loss of accessory factors before be- 

 coming completely autonomous neoplasms. 



4. The formation and growth of cancer cells are affected 

 by conditions within the host — the genetic constitution, the 

 hormone balance, the diet, the presence of irritation, chemo- 

 therapeutic agents — any factor that affects the internal en- 

 vironment of the host. 



It appears clear from the above points that the causes of 

 cancer may be varied and multiple and that the point of initia- 

 tion may be nuclear or cytoplasmic. It is also clear that the 

 metabolic patterns of neoplasms may include a diversity of 

 features which they have in common with normal cells. 



Course of Action 

 The concepts just presented are far from complete; at 



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