Are Serum Ferritin Levels a Reliable Cancer Biomarker? A Systematic Review and Meta-Analysis

Iron, Copper, and Selenium: Cancer's Thing for Redox Bling

Cells require micronutrients for numerous basic functions. Among these, iron, copper, and selenium are particularly critical for redox metabolism, and their importance is heightened during oncogene-driven perturbations in cancer. In this review, which particularly focuses on iron, we describe how these micronutrients are carefully chaperoned about the body and made available to tissues, a process that is designed to limit the toxicity of free iron and copper or by-products of selenium metabolism. We delineate perturbations in iron metabolism and iron-dependent proteins that are observed in cancer, and describe the current approaches being used to target iron metabolism and iron-dependent processes.

Ferritin and Ferritin-to-Hemoglobin Ratio as Promising Prognostic Biomarkers of Severity in Acute Pancreatitis-A Cohort Study

BACKGROUND

Acute pancreatitis is an inflammation of the pancreas with variable outcomes depending on its severity. Multiple systems of prediction have been proposed, each with variable specificity and sensitivity and with uneven clinical use. Ferritin is a versatile protein associated with various acute and chronic conditions.

AIMS

In our study, we aimed to assess the association of serum ferritin and the ferritin-to-hemoglobin ratio (FHR) with the severity of acute pancreatitis.

METHODS

A retrospective study was conducted in our hospital from January 2020 to September 2022 and included 116 patients with acute pancreatitis (graded according to the revised Atlanta classification). Serum ferritin and FHR were determined next to established laboratory parameters in the first 24 h following admission (hematological parameters, amylase, lipase, C-reactive protein, D-dimers, lactate dehydrogenase). We performed a receiver operating characteristic curve analysis for potential predictors. Also, we made correlations and conducted univariate and multivariate analyses for all potential severity biomarkers.

RESULTS

The median values of serum ferritin and FHR differed significantly between patients with severe acute pancreatitis and mild cases (serum ferritin: 352.40 vs. 197.35 ng/mL, p = 0.011; FHR: 23.73 vs. 13.74, p = 0.002) and between patients with organ failure and those without organ failure (serum ferritin: 613.45 vs. 279.65 ng/mL, p = 0.000; FHR: 48.12 vs. 18.64, p = 0.000). The medians of the serum ferritin and FHR levels were significantly higher in non-survivors compared with survivors (serum ferritin: 717.71 vs. 305.67 ng/mL, p = 0.013; FHR: 52.73 vs. 19.58, p = 0.016). Serum ferritin and FHR were good predictors for organ failure and mortality, next to D-dimers and procalcitonin (AUC > 0.753 for organ failure and AUC > 0.794 for mortality). In univariate regression analysis, serum ferritin and FHR were independent variables for moderate-severe forms of acute pancreatitis. Still, adjusting the multivariate analysis, only FHR remained a significant predictor. The cut-offs for serum ferritin and FHR for predicting organ failure were 437.81 ng/mL (sensitivity, 71%; specificity, 75%) and 45.63 (sensitivity, 61%; specificity, 88%), and those for mortality during hospitalization were 516 ng/mL (sensitivity, 83%; specificity, 74%) and 51.58 (sensitivity, 66%; specificity, 86%).

CONCLUSIONS

Serum ferritin and the ferritin-to-hemoglobin ratio stood out in this study as valuable and accessible predictors of disease severity in the early assessment of acute pancreatitis, next to established severity serum markers (CRP, fibrinogen, D-dimers).

Adsorption of Ferritin at Nanofaceted Al2O3 Surfaces

The influence of nanoscale surface topography on protein adsorption is highly important for numerous applications in medicine and technology. Herein, ferritin adsorption at flat and nanofaceted, single-crystalline Al2O3 surfaces is investigated using atomic force microscopy and X-ray photoelectron spectroscopy. The nanofaceted surfaces are generated by the thermal annealing of Al2O3 wafers at temperatures above 1000 °C, which leads to the formation of faceted saw-tooth-like surface topographies with periodicities of about 160 nm and amplitudes of about 15 nm. Ferritin adsorption at these nanofaceted surfaces is notably suppressed compared to the flat surface at a concentration of 10 mg/mL, which is attributed to lower adsorption affinities of the newly formed facets. Consequently, adsorption is restricted mostly to the pattern grooves, where the proteins can maximize their contact area with the surface. However, this effect depends on the protein concentration, with an inverse trend being observed at 30 mg/mL. Furthermore, different ferritin adsorption behavior is observed at topographically similar nanofacet patterns fabricated at different annealing temperatures and attributed to different step and kink densities. These results demonstrate that while protein adsorption at solid surfaces can be notably affected by nanofacet patterns, fine-tuning protein adsorption in this way requires the precise control of facet properties.

Analysis of Transferrin in the Urine of Patients with Bladder Cancer Using Nanobodies

It is known that the saturation ratio of transferrin (Tf) with iron in human blood is an important clinical parameter. Specific antibodies can be used to analyze subtle changes in the relative abundance of different forms of transferrin potentially associated with a pathological process. Recently, the authors of this study were able to obtain and characterize highly specific single-domain antibodies (nanobodies) that predominantly recognize the iron-saturated (holo-Tf) or iron-unsaturated (apo-Tf) form of transferrin. In this work, under conditions closer to physiological than in the previous experiments, we further demonstrated that these unique nanobodies have extremely high differential binding specificity for different forms of Tf in different human biological fluids. Using these nanobodies, we were able to analyze for the first time relative abundance of the transferrin forms in urine samples from the patients with bladder cancer (BC). We have shown that increase in the concentration of total Tf in the urine samples normalized for creatinine is associated with the degree of progress and growth of malignancy of BC. In the samples of healthy donors and in the early stages of BC (G1), Tf is detected in much smaller amounts (compared to the later stages) and only with additional concentration of the studied samples. For most of the studied urine samples from the BC patients, it is expected (as previously shown in the case of Tf in the blood of terminal ovarian cancer patients) that the concentration of apo-Tf is clearly higher than holo-Tf, especially in the case of the most advanced muscle-invasive BC. It was a surprise for us that approximately equal amounts of apo-Tf and holo-Tf were found in the urine samples of some patients with BC. We hypothesized that the holo-Tf fraction in this case could be largely represented by the "secondary complexes" formed by apo-Tf in combination with ions other than Fe3+, which accumulate in the urine of some cancer patients and are able to bind to apo-Tf, changing its conformation towards holo-Tf. By using inductively coupled plasma mass spectroscopy (ICP-MS), we obtained first results confirming our hypothesis. Preparation of the holo-Tf in these urine samples was found to be highly enriched in zinc and nickel. Also, relative enrichment in cadmium has been observed in this preparation, but at much lower concentrations. The obtained data indicate that the used nanobody, while recognizing predominantly the iron-saturated form of transferrin (holo-Tf), is also capable of binding transferrin in association with other metal ions that are different from iron. This ability could potentially open up new possibilities for investigation of relative abundance of various metal ions in association with transferrin in human biological fluids in normal and pathological conditions.

A novel view of ferritin in cancer

Since its discovery more than 85 years ago, ferritin has principally been known as an iron storage protein. However, new roles, beyond iron storage, are being uncovered. Novel processes involving ferritin such as ferritinophagy and ferroptosis and as a cellular iron delivery protein not only expand our thinking on the range of contributions of this protein but present an opportunity to target these pathways in cancers. The key question we focus on within this review is whether ferritin modulation represents a useful approach for treating cancers. We discussed novel functions and processes of this protein in cancers. We are not limiting this review to cell intrinsic modulation of ferritin in cancers, but also focus on its utility in the trojan horse approach in cancer therapeutics. The novel functions of ferritin as discussed herein realize the multiple roles of ferritin in cell biology that can be probed for therapeutic opportunities and further research.

Predicting acute radiation dermatitis in breast cancer: a prospective cohort study

BACKGROUND

Acute radiation dermatitis (ARD) is one of the most common acute adverse reactions in breast cancer patients during and immediately after radiotherapy. As ARD affects patient quality of life, it is important to conduct individualized risk assessments of patients in order to identify those patients most at risk of developing severe ARD.

METHODS

The data of breast cancer patients who received radiotherapy were prospectively collected and analyzed. Serum ferritin, high-sensitivity C-reactive protein (hs-CRP) levels, and percentages of lymphocyte subsets were measured before radiotherapy. ARD was graded (0-6 grade), according to the Oncology Nursing Society Skin Toxicity Scale. Univariate and multivariate logistic regression analyses were used and the odds ratio (OR) and 95% confidence interval (CI) of each factor were calculated.

RESULTS

This study included 455 breast cancer patients. After radiotherapy, 59.6% and 17.8% of patients developed at least 3 (3+) grade and at least 4 (4+) grade ARD, respectively. Multivariate logistic regression analysis found that body mass index (OR: 1.11, 95% CI: 1.01-1.22), diabetes (OR: 2.70, 95% CI: 1.11-6.60), smoking (OR: 3.04, 95% CI: 1.15-8.02), higher ferritin (OR: 3.31, 95% CI: 1.78-6.17), higher hs-CRP (OR: 1.96, 95% CI: 1.02-3.77), and higher CD3 + T cells (OR: 2.99, 95% CI: 1.10-3.58) were independent risk factors for 4 + grade ARD. Based on these findings, a nomogram model of 4 + grade ARD was further established. The nomogram AUC was 0.80 (95% CI: 0.75-0.86), making it more discriminative than any single factor.

CONCLUSION

BMI, diabetes, smoking history, higher ferritin, higher hs-CRP, and higher CD3 + T cells prior to radiotherapy for breast cancer are all independent risk factors for 4 + grade ARD. The results can provide evidence for clinicians to screen out high-risk patients, take precautions and carefully follow up on these patients before and during radiotherapy.

Nutritional Aspects of Iron in Health and Disease

Dietary iron assimilation is critical for health and essential to prevent iron-deficient states and related comorbidities, such as anemia. The bioavailability of iron is generally low, while its absorption and metabolism are tightly controlled to satisfy metabolic needs and prevent toxicity of excessive iron accumulation. Iron entry into the bloodstream is limited by hepcidin, the iron regulatory hormone. Hepcidin deficiency due to loss-of-function mutations in upstream gene regulators causes hereditary hemochromatosis, an endocrine disorder of iron overload characterized by chronic hyperabsorption of dietary iron, with deleterious clinical complications if untreated. The impact of high dietary iron intake and elevated body iron stores in the general population is not well understood. Herein, we summarize epidemiological data suggesting that a high intake of heme iron, which is abundant in meat products, poses a risk factor for metabolic syndrome pathologies, cardiovascular diseases, and some cancers. We discuss the clinical relevance and potential limitations of data from cohort studies, as well as the need to establish causality and elucidate molecular mechanisms.

Ferritin in pediatric critical illness: a scoping review

This scoping review aimed to elucidate and summarize the predictive role of serum ferritin in critical pediatric illness. The Preferred Reporting Items for Systematic reviews and Meta-Analyses methodology was employed to conduct a scoping review of 5 databases (MEDLINE, CENTRAL, ProQuest, ScienceDirect, and Epistemonikos) from the date of inception through January 24, 2022. Primary research studies involving subjects aged <18 years and serum ferritin levels were screened and reviewed independently following an a priori defined protocol. Of the 1,580 retrieved studies, 66 were analyzed. Summary statistics of serum ferritin levels for overall and condition-specific studies were reported in 30 (45.4%) and 47 studies (71.2%), respectively. The normal range was defined in 16 studies (24.2%), whereas the threshold was determined in 43 studies (65.1%). A value of <500 ng/mL was most often the upper limit of the normal range. Serum ferritin as a numerical variable (78.9%) was usually significantly higher (80.8%) in the predicted condition than in controls, while as a categorical variable with preset thresholds, ferritin was a significant predictor in 84.6% of studies. A total of 22 predictive thresholds predicted mortality (12 of 46 [26.1%]), morbidity (18 of 46 [39.1%]), and specific (16 of 46 [34.8%]) outcomes in 15 unique conditions. Increased precision in serum ferritin measures followed by close attention to the threshold modeling strategy and reporting can accelerate the translation from evidence to clinical practice.

Prognostic Value of Serum Transferrin Analysis in Patients with Ovarian Cancer and Cancer-Related Functional Iron Deficiency: A Retrospective Case-Control Study

(1) Background: There are no reliable and widely available markers of functional iron deficiency (FID) in cancer. The aim of the study was to evaluate the role of transferrin (Tf) as a marker of cancer of the ovary (CrO) and related FID. (2) Methods: The study groups consisted of 118 patients with CrO and 69 control females. Blood serum iron status was determined on a Beckman Coulter AU (USA) analyzer. Tf quantification was performed by immunoturbidimetry. The relative contents of apo- and holo-Tf (iron-free and iron-saturated Tf, respectively) were determined in eight patients and a control female by immunochromatographic analysis based on the use of monoclonal single-domain antibodies (nanobodies). (3) Results: Four groups of patients with different iron statuses were selected according to ferritin and transferrin saturation values: absolute iron deficiency (AID) (n = 42), FID (n = 70), iron overload (n = 4), normal iron status (n = 2). The groups differed significantly in Tf values (p < 0.0001). Lower values of Tf were associated with FID. Furthermore, FID is already found in the initial stages of CrO (26%). Immunosorbents based on nanobodies revealed the accumulation of apo-Tf and the decrease in holo-Tf in patients with CrO. (4) Conclusions: Tf may be a promising tool for diagnosing both CrO and associated FID.

Prognostic role of pretreatment serum ferritin concentration in lung cancer patients: A meta-analysis

BACKGROUND

The association between pretreatment serum ferritin concentration (SFC) and long-term survival in lung cancer remains unclear now.

AIM

To identify the prognostic value of pretreatment SFC in lung cancer patients based on current evidence.

METHODS

The PubMed, EMBASE and Web of Science databases were searched from inception to May 29, 2022 for relevant studies. The primary endpoint was overall survival (OS) and the hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were combined to assess the predictive role of pretreatment SFC for long-term survival of lung cancer patients. The data were then extracted and assessed on the basis of the Reference Citation Analysis (https://www.referencecitationanalysis.com/).

RESULTS

Twelve retrospective studies involving 1654 patients were analyzed. The results manifested that increased pretreatment SFC was associated with worse OS (HR = 1.09, 95%CI: 1.03-1.15, P = 0.004). Subgroup analysis stratified by the country (China vs non-China) showed similar results. However, subgroup analysis stratified by tumor type revealed inconsistent results (lung cancer: HR = 1.39, P = 0.008; small cell lung cancer: HR = 1.99, P = 0.175; non-small cell lung cancer: HR = 1.03, P = 0.281).

CONCLUSION

Pretreatment SFC might serve as a promising prognostic indicator in lung cancer patients and elevated pretreatment SFC predicts worse prognosis. However, more high-quality studies with big sample sizes are still needed to further verify its prognostic value in lung cancer.

M2 Macrophage-Derived Exosomal Ferritin Heavy Chain Promotes Colon Cancer Cell Proliferation

Colon cancer is a widespread life-threatening malignancy with complex and multifactorial etiology. Both epidemiological cohort studies and basic research support the substantial role of iron metabolism in colon cancer. Thus, understanding the mechanisms of how essential iron metabolic proteins are dysregulated may provide new treatment strategies for colon cancer. Ferritin is the main iron storage protein that occupies a vital position in iron metabolism. Studies reported that ferritin is differentially highly expressed in tissues from multiple malignancies. However, the source and function of highly expressed ferritin in colon cancer have not been explored. In this study, we found that the protein level but not RNA level of ferritin heavy chain (FTH1) was upregulated in colon cancer using paired clinical samples. Co-culture system was used to mimic the in vivo circumstance and study the cell-cell communication of macrophages and colon cancer cells. Results showed that M2 macrophages could substantially increase the FTH1 levels in colon cancer cells. This effect could be blocked by the exosome biogenesis/ secretion inhibitor GW4869, implying the vital role of exosomes in this biological process. Besides, we found that purified exosomes from M2 macrophages could deliver FTH1 into colon cancer cells and promote cell proliferation. Furtherly, EdU assay and live cell imaging system were performed in FTH1-OE (overexpression) colon cancer cell lines and confirmed the cell proliferation promoting effect of FTH1. Our results unveil the source and function of highly expressed FTH1 in colon cancer and provide a new potential therapeutic target for the treatment of colon cancer.

Iron-Induced Oxidative Stress in Human Diseases

Iron is responsible for the regulation of several cell functions. However, iron ions are catalytic and dangerous for cells, so the cells sequester such redox-active irons in the transport and storage proteins. In systemic iron overload and local pathological conditions, redox-active iron increases in the human body and induces oxidative stress through the formation of reactive oxygen species. Non-transferrin bound iron is a candidate for the redox-active iron in extracellular space. Cells take iron by the uptake machinery such as transferrin receptor and divalent metal transporter 1. These irons are delivered to places where they are needed by poly(rC)-binding proteins 1/2 and excess irons are stored in ferritin or released out of the cell by ferroportin 1. We can imagine transit iron pool in the cell from iron import to the export. Since the iron in the transit pool is another candidate for the redox-active iron, the size of the pool may be kept minimally. When a large amount of iron enters cells and overflows the capacity of iron binding proteins, the iron behaves as a redox-active iron in the cell. This review focuses on redox-active iron in extracellular and intracellular spaces through a biophysical and chemical point of view.

Autoantibody Against Ferritin Light Chain is a Serum Biomarker for the Detection of Liver Cirrhosis but Not Liver Cancer

Purpose

Ferritin is a protein that plays an important role in iron metabolism, it consists of two subunits: heavy chain (FTH) and light chain (FTL). Elevated expression of FTL is observed in multiple malignancies. Recent studies have found that the frequency of circulating autoantibody against FTL (anti-FTL) increased significantly in hepatocellular carcinoma (HCC). The aim of this study is to verify circulating anti-FTL as a biomarker for the early detection of HCC.

Patients and Methods

A total of 1565 participants were enrolled and assigned to two independent validation cohorts, including 393 HCC patients, 379 liver cirrhosis (LC) patients, 400 chronic hepatitis (CH) patients, and 393 healthy subjects. The concentration of serum anti-FTL was measured by indirect Enzyme-Linked Immunosorbent Assay (ELISA). Kruskal–Wallis test was used to compare anti-FTL concentrations between HCC group and three control groups. Percentile 95 of anti-FTL absorbance value of healthy group was selected as the cut-off value to calculate the positive rate in each group. The area under receiver operating characteristic curve (AUC) was used to quantitatively describe its diagnostic value.

Results

The median concentration of anti-FTL in HCC patients was higher than that in CH patients and healthy subjects, but there was no difference between HCC patients and LC patients. Further analysis showed that there was no difference between early stage LC, advanced stage LC, Child-Pugh A HCC, Child-Pugh B HCC and Child-Pugh C HCC. The positive rate of anti-FTL was 12.2% (48/393) in HCC, 13.5% (51/379) in LC, 6.3% (25/400) in CH and 5.1% (20/393) in healthy subjects, respectively. The AUC of anti-FTL to distinguish LC from CH or healthy subjects were 0.654 (95% CI: 0.615–0.692) and 0.642 (95% CI: 0.602–0.681), respectively.

Conclusion

Anti-FTL is not a biomarker for the early diagnosis of HCC due to specificity deficiency, but may be helpful for the early detection of LC.

Effect of Serum Ferritin on the Prognosis of Patients with Sepsis: Data from the MIMIC-IV Database

BACKGROUND

The present study aimed to investigate the prognostic value of serum ferritin in critically ill patients with sepsis by using the MIMIC-IV database.

METHODS

Data were extracted from the MIMIC-IV database. Adult patients who met the sepsis-3 criteria and had the test of ferritin were included. Patients were divided into subgroups according to the initial serum ferritin. The association between initial serum ferritin and in-hospital mortality was performed by using Lowessregression, logistic regression, and ROC analysis. Subgroup analysis was used to search for the interacting factors and verify the robustness of the results.

RESULTS

Analysis of the 2,451 patients revealed a positive linear relationship between serum ferritin and in-hospital mortality. Patients with high-ferritin had a higher risk of in-hospital mortality, but no significant association was found in the low-ferritin subgroup compared with those whose ferritin was in the normal reference range. Serum ferritin had moderate predictive power for in-hospital mortality (AUC = 0.651), with an optimal cut-off value of 591.5 ng/ml. Ferritin ≥591.5 ng/ml acted as an independent prognostic predictor of in-hospital mortality, which increased the risk of in-hospital mortality by 119%. Our findings were still robust in subgroup analysis, and acute kidney injury and anemia were considered interactive factors.

CONCLUSION

High-level serum ferritin was an independent prognostic marker for the prediction of mortality in patients with sepsis. Further high-quality research is needed to confirm the relationship between ferritin and the prognosis of septic patients.