Role of Natural Fluorescence of Human Blood Plasma in Patients With Colorectal Cancer.

The aim of the present prospective study was to investigate the fluorescence emission of human blood plasma of patients with colorectal cancer.

For years, serum tumor markers have been studied for the diagnosis and follow-up of colorectal cancer, among which carcinoembryonic antigen (CEA) has achieved promising results. However, the sensitivity of CEA for colorectal cancer is less than 25% and elevated CEA levels also occur in patients with benign disease, as well as in patients with other carcinomas. Nevertheless, surveillance programs are often based on the CEA test and combination with other markers is at present a matter of research. Alternative methods based on optical fluoroscopy have been introduced in experimental stages for clinical diagnosis of cancer. Few studies have been reported on the application of native fluorescence spectroscopy of biofluids in the diagnosis of tumoral diseases. The above reported findings prompted us to investigate the fluorescence emission of human blood plasma of patients with colorectal cancer. For this purpose, the blood of patients was collected and the fluorescence Preliminary measurements on plasma of patients bearing colon cancer showed that the fluorescence spectra were mainly characterized by the presence of an emission peaking at 620-630 nm, whose excitation spectrum peaked at 405 nm. Hence, an excitation wavelength of 405 nm was selected for the study. The fluorescence emission spectra were recorded in the range of 430-700 nm.