Plasma fibronectin in mammary and uterine carcinomas

Plasma fibronectin was determined in cancer patients and in age- and sex-matched controls and analyzed as a function of age, size of tumor, receptor content of the tumor, metastases and treatment. In the control population, plasma fibronectin increased with age exponentially. The age-dependent increase in plasma fibronectin was strongly attenuated in the cancer population. As normal and cancer curves intersect at about 40-46 years, below this age cancer plasmas have slightly higher values than normal, above this age the inverse is true. No correlation was found between estrogen or progesterone receptor levels and plasma fibronectin values, nor with plasma albumin. Tumor patients with distant metastases gave slightly but significantly higher values than those with local or no metastases. No significant difference was found between tumors when Bloom grading was taken as the second parameter instead of age. The size of the tumor or the type of treatment had no influence. Increased proteolytic activity, increased trapping of plasma fibronectin in tissues and especially in the stromal (desmoplastic) reaction and/or modifications in plasma fibronectin biosynthesis may well be responsible for these results.