CANCER RESEARCH 31 



We mentioned already that certain pathological conditions prepare 

 the soil for the subsequent development of cancer, such as for instance 

 lupus, chronic ulceration of the leg. But there are numerous other 

 morbid conditions which stand in a certain causal relation to the 

 growth of cancer. Gastric carcinoma originates in a considerable num- 

 ber of cases at the site of a previous ulcer of the stomach. Long-con- 

 tinued suppuration in the middle ear, fistules of various parts of the 

 body may be followed by the development of cancer; so may certain 

 affections, in which either certain parts of the skin or the mucosa are 

 covered by plaques of horn, so-called (leukoplakia of the tongue and 

 vulva, psoriasis). In the mammary gland chronic inflammation may 

 lead to the subsequent development of cancer. Carcinoma may be pre- 

 ceded in the thyroid by goitre, in the liver, by chronic inflammation 

 leading to an increase in fibrous tissue (cirrhosis), in the prostate by 

 hypertrophy which is relatively common in old men. Inasmuch as cer- 

 tain conditions predisposing to cancer may be caused by syphilis, also 

 syphilitic infection is indirectly one of the causes of cancer. 



We mentioned previously that xeroderma pigmentosum, a congenital 

 lesion of the skin, becomes usually cancerous. We furthermore know 

 that certain at first benign tumors may later be transformed into 

 cancers. Thus papillomata (polypus or cauliflower-like outgrowths) 

 very often precede cancer of the small and large intestines or of the 

 bladder. These papillomata are in the intestines frequently caused by 

 preceding long-continued irritation; in certain cases however they are 

 congenital. Pigmented moles of the skin if constantly irritated may be 

 transformed into a pigmented cancer which is often very virulent. 



At first benign tumor-like proliferations of the epithelium of the 

 liver, mammary gland, ovaries, uterus, and especially glandular tumors 

 (so-called adenomata) may later become transformed into carcinoma. 

 As we have already mentioned, certain parts of teratomata at various 

 places of the body are not rarely changed into carcinoma or sarcoma. 

 The usually benign muscle tumors of the uterus (myomata) are in 6-10 

 per cent, of all the cases transformed into tumors resembling sarcomata, 

 a change which does usually not take place before the patient has 

 reached the fortieth year. In other cases, however, such myomata of the 

 uterus are only the indirect cause of the development of cancer, the 

 mucosa in their neighborhood becoming converted into carcinoma. Pos- 

 sibly the constant irritation caused through the pressure of the muscle 

 tumors upon the epithelial lining of the organ may be responsible for 

 this transformation. Furthermore, fat tumors (lipomata) may occa- 

 sionally assume a malignant growth and become sarcomatous or soft, 

 mucus-producing tumors (myxomata) which may be malignant and 

 may metastasize. 



Long-continued irritation is not always necessary but in certain 



