Tumor-induced disorder of iron metabolism in major organs: a new insight from chemical speciation of iron

Objective To investigate the evolution of iron speciation in major organs of tumor-bearing mice and its role in cancer formation and cancer-associated complications. Methods The concentration and chemical speciation of iron in the spleen, liver, lung, kidney, heart, blood, muscle, and tumor tissue of healthy mice and tumor-bearing mice were studied by synchrotron radiation-based total reflection X-ray fluorescence spectrometry (SR-TXRF) coupled with X-ray absorption spectroscopy (XAS). Results The TXRF and XAS results showed that the iron content, especially the ferritin content, significantly decreased in the blood and spleen but significantly increased in the liver, lung, and muscle of mice after tumor implantation. The chemical speciation of iron in the tumor mainly comprised ferrous-sulfide-like iron and ferritin. Conclusion The tumors disturbed the iron metabolism in major organs, and the evolution of iron may be involved in iron deficiency anemia, cancer growth, and immunity. Additionally, iron speciation-based markers may be further developed as clinical indicators for cancer and cancer-associated complications.