Blood porphyrin fluorescence peaks and its diagnostic value for early colorectal cancer (crc) detection

Emran Emami,1,* Hamid keshvari,2 Zahra hassannejad,3 Mohammad hassan emami,4

1. Gastrointestinal and Hepatobiliary Diseases Research Center
2. Amirkabir University of Technology
3. Pediatric Urology and Regeneration Medicine Research Center
4. Gastrointestinal and Hepatobiliary Diseases Research Center, MUI



Porphyrins are precursors of heme metabolism. any metabolic disorder like cancer can highly affect their level. since they’re natural fluorophores, it’s easy to trace them in blood. that’s why the blood porphyrin fluorescence peak alteration is frequently considered as a promising cancer biomarker. the aim of current work is to answer this question: considering the clinical and laboratorial limitations, could porphyrin be a promising biomarker for crc?


Different fluorescence spectrum of both plasma and whole blood of two groups of healthy and crc subjects were gained. based on previous reports and practical experiences, the optimum fluorescence spectrophotometry conditions were chosen for excitation and the porphyrin characteristic peak around 630nm was used as criterion for crc detection. moreover, for a better detection, an improved approach was applied as following: blood samples were excited at 450nm and the emission spectra was used as a background filter such that porphyrin peaks were uncovered more distinctly. in addition, excitation-emission-matrix (eem) was achieved.


Despite bunch of former reports showing the ability of porphyrin peaks to differentiate between crcs and healthy subjects accurately, no prominent differences were observed in the current study. neither in blood samples nor in plasma. even distinct porphyrin peaks that are detected from total spectra by a novel trick, couldn’t show any differentiation. nevertheless, a prominent peak around 500nm was observed.


Despite frequent reports around promising early cancer diagnosing by porphyrin level in blood, current results proved that it might not be reliable for crc detection. it may be caused from several unavoidable limitations affecting the porphyrin fluorescence including: laboratorial limitations (operator based errors), conflicting disorders (other disorders affecting porphyrin level as well e.g. anemia) and environmental interferers (lifestyle and habits e.g. smoking). so we propose using other peaks (i.e. 500nm) or eem alternatively.


Blood porphyrin, fluorescence spectroscopy, early cancer detection, diagnostic value, colorectal can