Cancer Detection by Serum Fluorescence Analysis: A Spectroscopic Study

Objective To investigate the significance of serum fluorescence analysis for cancer detection, a diagnostic method for malignancies at molecular and electronic levels. Methods Blood serum was prepared and its luminescence center was studied using photoinduced luminescence techniques. Effects of the presence of malignant tumors on porphyrin and carotenoid metabolism in the organism were analyzed. The judgment of presence of cancers was carried out by measuring the relative content of porphyrins to carotenoids and by induction of an empirical function. Results Spectroscopic examination of human blood serum showed that the main luminescent molecules in serum are proteins, porphyrins and carotenoids, and the porphyrin and carotenoid metabolism was impaired in cancer patients. The porphyrin level in serum was highly increased in the earlier stage of cancer development and then gradually descended with the advance of the tumors. The carotenoid level was prominently increased in the advanced stage of cancer development. An analysis using an empirical formula, Ⅰ=Ⅰ A/Ⅰ B-1, the coincidence rate of cancer detection with clinical diagnosis reached 90% in a group of 1215 cancer patients, including malignant tumors in stomach, liver, lungs, breast, colon, esophagus, uterus or other organs. Conclusions The porphyrin metabolism is abnormally changed in cancer patients and protoporphyrin Ⅸ can be used as a biomarker in cancer detection. An empirical formula was induced by analysis of measurement of relative content of protoporphyrin Ⅸ and it can well be applied in cancer detection in clinical practice.