182 F. HAGUENAU AND K. H. HOLLMANN 



lipid droplets for instance but these are not accompanied by the typi- 

 cal arrangement referred to here. On the whole, ergastoplasm in human 

 breast cancer is not abundant and is not present in its "organized" form 

 (Fig. lo). 



This description, however, would lead to an erroneous representation 

 were it not completed by another important feature directly related to the 

 problem of nucleic acids in cancer cells. This concerns the A and B 

 types of cells described by Caspersson and Santesson [13] in the course of 

 their studies with ultraviolet absorption technique. These two basic types 

 of cells were characterized by, the A cell "a well-developed cytoplasmic 

 protein-forming system", the B cell, "a nucleolar apparatus showing 

 signs of intense function but practically none of protein or nucleic acid 

 formation in the cytoplasm" (Caspersson [14], pp. 142-145) (Fig. 11). 



Other authors have confirmed this description though often using a 

 different appellation for the two types of cells [15, 16, 17, 18]. Their exis- 

 tence is important since a relation could be established between the type 

 of cells present in tumours and sensitivity to radiation [15, 17, 18, 19, 20, 

 21 , 22]. The consequences of this from a prognostic as well as a therapeutic 

 point of view would justifv greater development but would lead us into 

 the whole chapter of the relation between irradiation, growth, differentia- 

 tion, ageing and death of the cell. 



What matters to us here is that in the electron microscope, two types 

 of cells corresponding roughly to those originally described by Caspersson 

 and Santesson may be readily observed [10, 11] (Fig. 12). 



Though a simultaneous spectrophotometric and electron microscopic 

 study of the same cells has still not been achieved, parallel cytochemical 

 studies (methyl-green-pyronin and fluorescent acridine orange stains) 

 leave little place for doubt on the subject. 



Though A cells are formed in all types of cancer studied in the electron 

 microscope so far, they are particularly noticeable in breast cancers. Not 

 all of these contain them nor are they present in cancers only. They can 

 be observed in hormone-stimulated glands or in benign tumours. In this 

 case their number is always small and their localization at the periphery 

 of a lobule. This corresponds to the typical localization noticed by 

 Caspersson and Santesson. In breast cancers, however, not only can their 

 number be greatly increased but the peripheral arrangement is no longer 

 respected. 



In the electron microscope the morphological characteristics of A and 



Fig. II. A and B cells in human mammary cancers as seen in the ultraviolet 

 microscope. The difference of absorption at 2570 A wavelength is very obvious 

 between the two types of cells, x 770 and x 550. 



(By courtesy of Prof. T. O. Caspersson) 



