Experimental colon neoplasia enhanced by extract of sperm (protamine)

An experimental study of colorectal tumorigenesis in inbred rats given the potent carcinogen dimethylhydrazine has shown that protamine, given before any tumours had developed, significantly enhanced the development of large bowel tumours (100% incidence). Those animals having no adjuvant therapy or who received either heparin or 5-fluorouracil (alone or in combination) had an approximate 50% incidence of such tumours.