Ferritinaemia in cancer

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.

Infected erythrocytes and plasma proteomics reveal a specific protein signature of severe malaria

Cerebral malaria (CM), the most lethal complication of Plasmodium falciparum severe malaria (SM), remains fatal for 15-25% of affected children despite the availability of treatment. P. falciparum infects and multiplies in erythrocytes, contributing to anemia, parasite sequestration, and inflammation. An unbiased proteomic assessment of infected erythrocytes and plasma samples from 24 Beninese children was performed to study the complex mechanisms underlying CM. A significant down-regulation of proteins from the ubiquitin-proteasome pathway and an up-regulation of the erythroid precursor marker transferrin receptor protein 1 (TFRC) were associated with infected erythrocytes from CM patients. At the plasma level, the samples clustered according to clinical presentation. Significantly, increased levels of the 20S proteasome components were associated with SM. Targeted quantification assays confirmed these findings on a larger cohort (n = 340). These findings suggest that parasites causing CM preferentially infect reticulocytes or erythroblasts and alter their maturation. Importantly, the host plasma proteome serves as a specific signature of SM and presents a remarkable opportunity for developing innovative diagnostic and prognostic biomarkers.

FTH1 indicates poor prognosis and promotes metastasis in head and neck squamous cell carcinoma

Background

Currently, ferritin heavy chain (FTH1) has been increasingly found to play a crucial role in cancer as a core regulator of ferroptosis, while its role of non-ferroptosis in head and neck squamous cell carcinoma (HNSCC) is still unclear.

Methods

Herein, we analyzed the expression level of FTH1 in HNSCC using TCGA database, and FTH1 protein in HNSCC tissues and cell lines was determined by immunohistochemistry (IHC) and western blotting, respectively. Then, its prognostic value and relationship with clinical parameters were investigated in HNSCC patients. Additionally, the biological function of FTH1 in HNSCC was explored.

Results

The current study showed that FTH1 is significantly overexpressed in HNSCC tissues and related to poor prognosis and lymph node metastasis of HNSCC. FTH1 knockdown could suppress the metastasis and epithelial-mesenchymal transition (EMT) process of HNSCC.

Conclusion

Our findings indicate that FTH1 plays a critical role in the progression and metastasis of HNSCC and can serve as a promising prognostic factor and therapeutic target in HNSCC.

Prognostic Value of Ferritin-to-Hemoglobin Ratio in Patients with Advanced Non-Small-Cell Lung Cancer

Background: Among commonly used biomarkers that reflect overall health in patients with cancer, hemoglobin is an iron-containing, oxygen-carrying protein in red blood cells, and serum ferritin is an iron-storage protein. This study investigated the ability of the ferritin-to-hemoglobin ratio to predict survival in patients with advanced non-small-cell lung cancer (NSCLC).

Methods: The medical records of patients with pathologically confirmed advanced NSCLC were retrospectively reviewed. The ferritin level, hemoglobin level, and ferritin-to-hemoglobin ratio at the initiation of treatment were investigated. After descriptive analysis of the ferritin-to-hemoglobin ratio, the optimal diagnostic cutoff value for survival was determined using receiver operating characteristic analysis. After dichotomizing patients according to the optimal cutoff value, the prognostic effect of the ferritin-to-hemoglobin ratio was assessed. Overall survival (OS) was calculated using Kaplan-Meier analysis and compared using log-rank tests. Cox proportional hazards regression was used to evaluate the prognostic effect with respect to survival.

Results: Of the enrolled patients, 91.3% had stage IV NSCLC, 42.0% had an Eastern Cooperative Oncology Group-performance status (ECOG-PS) score of 2, and 56.5% previously underwent systemic chemotherapy. The median OS of enrolled patients was 11.5 months. The range of the ferritin-to-hemoglobin ratio was 0.6-294.2, and the optimal cutoff value of the ferritin-to-hemoglobin ratio for survival was 13.0 (sensitivity, 58.5%; specificity, 80.0%; area under the curve = 0.68; P = 0.004). The median OS of patients with a low ferritin-to-hemoglobin ratio (<13.0) was 19.7 months, whereas that of patients with a high ferritin-to-hemoglobin ratio (≥13.0) was 8.5 months (P < 0.001). After eliminating confounding factors such as age, sex, ECOG-PS, histologic type, and C-reactive protein level, a high ferritin-to-hemoglobin ratio was significantly associated with poor survival. The multivariate proportional hazards model revealed that the ferritin-to-hemoglobin ratio was an independent prognostic marker for survival (hazard ratio, 1.91; 95% confidence interval, 1.27-2.88; P = 0.002).

Conclusion: The ferritin-to-hemoglobin ratio, a potential parameter of tumor progression, was a significant prognostic factor for OS, with a direct correlation to survival time in patients with advanced NSCLC.

Elevated plasma ferritin in elderly individuals with high neocortical amyloid-β load

Ferritin, an iron storage and regulation protein, has been associated with Alzheimer's disease (AD); however, it has not been investigated in preclinical AD, detected by neocortical amyloid-β load (NAL), before cognitive impairment. Cross-sectional analyses were carried out for plasma and serum ferritin in participants in the Kerr Anglican Retirement Village Initiative in Aging Health cohort. Subjects were aged 65-90 years and were categorized into high and low NAL groups via positron emission tomography using a standard uptake value ratio cutoff=1.35. Ferritin was significantly elevated in participants with high NAL compared with those with low NAL, adjusted for covariates age, sex, apolipoprotein E ɛ4 carriage and levels of C-reactive protein (an inflammation marker). Ferritin was also observed to correlate positively with NAL. A receiver operating characteristic curve based on a logistic regression of the same covariates, the base model, distinguished high from low NAL (area under the curve (AUC)=0.766), but was outperformed when plasma ferritin was added to the base model (AUC=0.810), such that at 75% sensitivity, the specificity increased from 62 to 71% on adding ferritin to the base model, indicating that ferritin is a statistically significant additional predictor of NAL over and above the base model. However, ferritin's contribution alone is relatively minor compared with the base model. The current findings suggest that impaired iron mobilization is an early event in AD pathogenesis. Observations from the present study highlight ferritin's potential to contribute to a blood biomarker panel for preclinical AD.

Diagnostic Potential of Carcinoembryonic Antigen and Ferritine in Tuberculous and Malignant Pleural Effusion

The aim of the study was to determine the diagnostic value of carcinoembryonic antigen (CEA) and ferritine in malignant and tuberculous non-bloody pleural effusion. The etiology of diseases was determined by cytologic, histologic and microbiologic methods. CEA concentration above 5 ng/ml and ferritine concentration above 200 ng/ml were considered to be positive. There was significant difference in the value of CEA measured in malignant and in tuberculous pleural effusion (P < 0.005) as well as in the sera (P < 0.01) of these two groups. There was no correlation between concentration of CEA and ferritine in malignant pleural effusion. Ratio between CEA and ferritine in effusions and sera was of no help in discrminating malignant from tuberculous effusions. No correlation between examined markers and physical status of patients was observed. The sensitivity and specificity of CEA assay in malignant pleural effusion was 65% and 90%, respectively, and for ferritine 67% and 80%, respectively. A high correlation was observed between the CEA concentration in malignant pleural effusion and sera patients (r = 0.95). Combined sensitivity and specificity of CEA and ferritine was 65.9% and 85%. Bayes theorem was used to calculate the positive predictive values for CEA and ferritine, which were 53% and 37%, respectively. Results obtained in the study show the relatively good diagnostic potential of CEA.

Preoperative Evaluation of Ferritinemia in Primary Epithelial Ovarian Cancer

Aims and background

High ferritin serum levels have been reported in patients suffering from various malignancies. The aim of this study was to evaluate the role of ferritinemia in the preoperative diagnosis of ovarian carcinoma.

Methods

Between March 1993 and September 1996, 60 patients suffering from ovarian carcinoma were surgically treated at our Department. Their ferritin serum levels were measured preoperatively by a solid-phase, two-site chemiluminescent immunometric assay and compared with those of a group of 60 healthy, age-matched, non pregnant controls.

Results

The mean serum concentration of ferritin was 54.7 ± 7.8 ng/ml (range, 14–135) in healthy controls and 112.3 ± 21.2 ng/ml (range, 9–947) in patients with ovarian carcinoma. The difference was statistically significant (P = 0.005, X2 test = 7.951). Serum ferritin was elevated preoperatively (cutoff ≥ 120 ng/ml) in 18/60 patients with malignancy (sensitivity 30%), whereas the CA 125 levels were above the cutoff in 53/60 patients (sensitivity 88.3%). Only 2/60 women of the control group had ferritin titers > 120 ng/ml (specificity 96.7%). The ferritin levels increased with advancing disease stage; no significant correlation was found between ferritin concentration and neoplastic histology and grading. The mean serum iron levels were also measured preoperatively in patients with ovarian carcinoma and healthy controls. They were 57.2 ± 3.8 and 66.3 ± 2.61 μg/dl, respectively, and the difference was not significant (P = 0.655, X2 test= 0.200).

Conclusions

The present study underlines that although ferritin shows an elevated specificity, its low sensitivity does not suggest any true usefulness as a tumor marker in epithelial ovarian cancer.

Immunological Reactivity of Serum Ferritin in Patients with Malignancy

Serum ferritin has been suggested as a tumor marker in the diagnosis of certain malignancies and for following the activity or dissemination of the malignant process. Since neoplastic tissues generally contain more acidic isoferritins than their normal tissue counterparts, it has also been suggested that the specific assay of such isoferritins in serum may be of particular value in the diagnosis of malignancy. In this work, we have evaluated ferritin concentration in the serum of normal subjects and patients with acute nonlymphocytic leukemia, Hodgkin's disease, breast cancer and lung cancer by simultaneously using three different immunoassays: an immunoradiometric assay based on polyclonal antibodies against human liver (basic, L-subunit rich) ferritin, a radioimmunoassay based on polyclonad antibodies against HeLa cell (acidic, H-subunit rich) ferritin, and an immunoradiometric assay based on the monoclonal antibody 2A4 raised against human heart (acidic, H-subunit rich) ferritin. Most of the patients studied had increased values for liver-type ferritin in the absence of increased iron stores. Binding of serum ferritin to concanavalin A did not prove to be useful in distinguishing a tumor-specific basic isoferritin. The HeLa ferritin assay was found to be less specific than the heart ferritin assay in the detection of acidic isoferritins, and did not provide any advantage over the liver assay in detecting the increased levels of serum ferritin associated with malignant disease. Heart-type ferritin was found in one-fifth of normal sera and 64% of sera from patients with malignancy. Values were very low compared with those for basic ferritin, ranging from less than 0.1 to 17% of total serum ferritin (geometric mean value 1.3%) in patients with malignancy. These findings indicate that at present there is little application for serum ferritin immunoassays based on antibodies to HeLa cell or heart ferritin in the diagnosis or monitoring of malignant disease. This seems to be due to the presence in human serum of biding factors which are responsible for the rapid clearance of acidic isoferritins from the circulation. The serum concentration of basic ferritin, however, can be useful in the diagnosis and management of some malignancies, and it is possible that studies on cell isoferritins can be important in biologic monitoring of neoplastic disorders. It should also be noted that the increased levels of serum ferritin found in patients with malignancy can exert adverse effects on the host immune response and perhaps an inhibitory effect on hematopoiesis.

Significance of Ferritin as a Marker in Head and Neck Malignancies

The efficiency of the combination of two tumor-associated antigens in recognising head and neck cancer was evaluated. The markers studied were CEA and ferritin by radioimmunoassay. CEA was estimated in 22 controls and 41 head and neck cancer patients. There was no difference in CEA values of controls and head and neck cancer patients, suggesting that CEA was not specific for head and neck malignancies. We measured serum ferritin in 27 controls and 58 patients with head and neck cancer. The mean ferritin level was significantly higher in patients (P < 0.001) than in normal subjects. The ferritin level in patients with no evidence of clinical disease 8 months after treatment showed approximately normal levels, whereas the levels showed a tendency to increase or remain at high levels in patients with a poor prognosis, giving support to the contention that ferritin may prove to be a valuable adjunct in head and neck cancer.

Ferritin Immunohistochemical Localization in Normal and Neoplastic Colonic Mucosa

High levels of ferritin have been detected in serum and tumoral extracts of gastrointestinal neoplasms. However, its histological localization is not well known. An immunoperoxidase technique (PAP) was used for detecting ferritin in 30 colorectal carcinomas, 20 polyps and 8 cases of non-neoplastic mucosae. Ferritin staining was detected in stromal cells (98%) much more than in epithelial cells (21%). Connective cells were positive in 5 cases of normal mucosae (62%), 19 polyps (95%) and all carcinomas (100%). The number of positive cells gradually rose from normal mucosa to carcinoma with an intermediate score in adenomas. However, no relation could be found between the stromal ferritin score and dysplasia in polyps. Likewise, no relation was found between the stromal ferritin score and the differentiation grade, invasion or metastases in carcinomas. The positive epithelial pattern seen in 12 cases (21%) suggests non-specific staining due to passive diffusion from the stroma. Thus, these immunohistochemical findings suggest that in colonic neoplasms, ferritin could be a tumor marker produced mainly by stromal cell reaction more than by the epithelial cells.

Clinical characteristics, therapy response, and outcome of 51 adult patients with hematological malignancy-associated hemophagocytic lymphohistiocytosis: a single institution experience

Hemophagocytic lymphohistiocytosis (HLH) is an underdiagnosed but life-threatening syndrome of hyperinflammation often occurring in adults with hematological malignancies (hM-HLH). The aim of the study was to describe clinical characteristics, therapy response, and outcome of adults with hM-HLH. The study included 51 adults with hM-HLH aged 23-84 years. Hyperferritinemia ≥500 µg/L was present in 96% of patients. The serum concentration of sIL-2Rα ≥ 2400 U/mL was revealed in 94% of patients. Twenty-three patients (45%) responded to therapy and achieved remission of HLH. The probability of overall survival (OS) at 6, 12, 24, and 60 months after HLH diagnosis were 42, 20, 15, and 15%, respectively. Patients with HLH during chemotherapy showed longer OS (median 124 days) than the patients who had HLH solely attributed to malignancy (median 65 days), but this difference was not statistically significant. Awareness of HLH in lymphoid and myeloid malignancies is crucial for improved survival.

Prognostic Significance of Host-related Biomarkers for Survival in Patients with Advanced Non-Small Cell Lung Cancer

OBJECTIVE

This study identified host-related prognostic biomarkers for survival in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

This study was based on the retrospective review of the medical records of 135 patients with pathologically confirmed advanced NSCLC. The host-related biomarkers assessed in this study that reflected patient condition included hemoglobin (Hb) levels; platelet (PLT), neutrophil, lymphocyte, and monocyte counts; and ferritin concentrations. The overall survival (OS) was calculated by Kaplan-Meier analysis and compared using log-rank tests. Univariate and multivariate analyses of Cox proportional hazards regression were used to evaluate the prognostic impact for survival.

RESULTS

Of the enrolled patients, 91.1% had stage IV NSCLC, 42.2% had ECOG-PS scores of 2, and 57% had undergone multiple rounds of prior systemic therapy. The prognostic factors included low Hb concentration (men: Hb < 13 g/dL, women: Hb < 12 g/dL; p = 0.046), increased neutrophil count (> 7,700 cells/μL; p < 0.001), decreased lymphocyte count (≤ 1500 cells/μL; p = 0.011), increased monocyte count (> 800 cells/μL; p < 0.001), and high ferritin level (men: > 200 ng/mL, women: > 150 ng/mL; p < 0.001), which were associated with poor OS and increased hazard of mortality. The multivariate proportional hazards model revealed that lymphocyte count, monocyte count, and ferritin level were independent host-related prognostic biomarkers for survival. Increased monocyte count (HR, 3.15; 95% CI, 1.64-6.04; p < 0.001) and high ferritin level (HR, 1.81; 95% CI, 1.24-2.64; p = 0.002) were significantly associated with poor survival, whereas increased lymphocyte count (HR, 0.57; 95% CI, 0.40-0.83; p = 0.004) showed prolonged survival.

CONCLUSION

Immune factors, such as lymphocyte and monocyte counts, as well as serum ferritin levels, are significant host-related prognostic biomarkers for survival with direct relevance to survival time in patients with advanced NSCLC.

Multi-factors including Inflammatory/Immune, Hormones, Tumor-related Proteins and Nutrition associated with Chronic Prostatitis NIH IIIa+b and IV based on FAMHES project

Chronic prostatitis (CP) is a complex disease. Fragmentary evidence suggests that factors such as infection and autoimmunity might be associated with CP. To further elucidate potential risk factors, the current study utilized the Fangchenggang Area Male Health and Examination Survey (FAMHES) project; where 22 inflammatory/immune markers, hormone markers, tumor-related proteins, and nutrition-related variables were investigated. We also performed baseline, regression, discriminant, and receiver operating characteristic (ROC) analyses. According to NIH-Chronic Prostatitis Symptom Index (NIH-CPSI), participants were divided into chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS, pain ≥ 4; divided into IIIa and IIIb sub-groups) and non-CPPS (pain = 0; divided into IV and normal sub-groups). Analyses revealed osteocalcin as a consistent protective factor for CP/CPPS, NIH-IIIb, and NIH-IV prostatitis. Further discriminant analysis revealed that ferritin (p = 0.002) and prostate-specific antigen (PSA) (p = 0.010) were significantly associated with NIH-IIIa and NIH-IV prostatitis, respectively. Moreover, ROC analysis suggested that ferritin was the most valuable independent predictor of NIH-IIIa prostatitis (AUC = 0.639, 95% CI = 0.534–0.745, p = 0.006). Together, our study revealed inflammatory/immune markers [immunoglobulin E, Complement (C3, C4), C-reactive protein, anti-streptolysin, and rheumatoid factors], hormone markers (osteocalcin, testosterone, follicle-stimulating hormone, and insulin), tumor-related proteins (carcinoembryonic and PSA), and a nutrition-related variable (ferritin) were significantly associated with CP or one of its subtypes.

Serum Ferritin as a Prognostic Biomarker for Survival in Relapsed or Refractory Metastatic Colorectal Cancer

Background: This study investigated the prognostic impact of serum ferritin for survival in patients with relapsed or refractory metastatic colorectal cancer (mCRC).

Methods: This retrospective cohort study reviewed clinicopathological characteristics and laboratory biomarkers in 120 mCRC patients being treated with Korean Medicine (KM). The overall survival (OS) of patients was calculated using the Kaplan-Meier method, and statistical significance was assessed using the log-rank test. Univariate and multivariate analyses of Cox proportional hazards regression were used to evaluate the prognostic impact for survival in relapsed or refractory mCRC patients.

Results: Of the patients, 62.5% had liver metastases, 74.1% underwent greater than second-line chemotherapy, and 80.8% underwent surgery. Median OS was 7.6 months for all patients after the initiation of KM treatment, which was begun 13.7 months, on average, after mCRC diagnosis. Concerning prognostic factors such as the presence of liver metastasis (p = 0.024), high carcinoembryonic antigen level (CEA > 5 ng/mL, p = 0.044), elevated C-reactive protein (CRP ≥ 10.0 mg/L, p = 0.000), high absolute monocyte count (AMC > 413.3 cells/μL, p = 0.034), elevated serum ferritin (ferritin ≥ 150 ng/mL, p = 0.002), low hemoglobin level (Hb < 12 g/dL, p = 0.026) and low albumin (albumin < 3.5 g/dL, p = 0.003) were associated with increased hazard ratios and poor survival. According to the multivariate proportional hazards model with backward and forward manners, albumin (albumin < 3.5 g/dL; hazard ratio (HR) 2.218, 95% confidence interval (CI) 1.135 - 3.990, p = 0.019), CRP (CRP ≥ 10.0 mg/L; HR 2.506, 95% CI 1.644 - 3.822, p = 0.000), CEA (CEA > 5 ng/mL; HR 2.040, 95% CI 1.203 - 3.460, p = 0.008), and serum ferritin (ferritin ≥ 150 ng/mL; HR 1.763, 95% CI 1.169 - 2.660, p = 0.007) were independent prognostic biomarkers of survival in mCRC patients.

Conclusions: These results indicate that serum ferritin acts as an independent prognostic biomarker for survival in relapsed or refractory mCRC patients.

Diagnostic Value of Common Inflammatory Markers on Fever of Unknown Origin

This study was designed to evaluate the diagnostic value of common inflammatory markers with regard to fever of unknown origin (FUO). We investigated 383 patients who were hospitalized with FUO at the Henan Province People's hospital between January 2009 and June 2015. Of all the cases, infectious diseases accounted for 33.9%, neoplasms for 21.1%, collagen vascular diseases for 25.1%, miscellaneous diseases for 4.7%, and no diagnosis for 15.1%. Patients in the neoplasm group were older than those in the infectious disease, collagen vascular disease, and miscellaneous disease groups (p = 0.006, p < 0.0001, and p = 0.001, respectively). The duration of fever before admission of patients in the neoplasm and collagen vascular disease group was longer than that of patients in the infectious disease group (p = 0.002 and p = 0.007, respectively). The diagnostic time after admission of patients from the neoplasm and collagen vascular disease groups was longer than that for patients from the infectious disease group (both p < 0.0001). Serum ferritin levels of patients in the infectious disease group were lower than those of patients in the neoplasm and collagen vascular disease groups (p = 0.029 and p = 0.032, respectively), while serum procalcitonin (PCT) levels in the infectious disease group was higher than that in the neoplasm and collagen vascular disease groups (p = 0.016 and p = 0.007, respectively). Therefore, FUO remains a clinical problem in China and serum ferritin and PCT may be useful in discriminating infectious from non-infectious causes (neoplasms and collagen vascular diseases) in patients with FUO.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

The significance of ferritin in cancer: anti-oxidation, inflammation and tumorigenesis

The iron storage protein ferritin has been continuously studied for over 70years and its function as the primary iron storage protein in cells is well established. Although the intracellular functions of ferritin are for the most part well-characterized, the significance of serum (extracellular) ferritin in human biology is poorly understood. Recently, several lines of evidence have demonstrated that ferritin is a multi-functional protein with possible roles in proliferation, angiogenesis, immunosuppression, and iron delivery. In the context of cancer, ferritin is detected at higher levels in the sera of many cancer patients, and the higher levels correlate with aggressive disease and poor clinical outcome. Furthermore, ferritin is highly expressed in tumor-associated macrophages which have been recently recognized as having critical roles in tumor progression and therapy resistance. These characteristics suggest ferritin could be an attractive target for cancer therapy because its down-regulation could disrupt the supportive tumor microenvironment, kill cancer cells, and increase sensitivity to chemotherapy. In this review, we provide an overview of the current knowledge on the function and regulation of ferritin. Moreover, we examine the literature on ferritin's contributions to tumor progression and therapy resistance, in addition to its therapeutic potential.

Novel chelators for cancer treatment: where are we now?

SIGNIFICANCE

Under normal circumstances, cellular iron levels are tightly regulated due to the potential toxic effects of this metal ion. There is evidence that tumors possess altered iron homeostasis, which is mediated by the perturbed expression of iron-related proteins, for example, transferrin receptor 1, ferritin and ferroportin 1. The de-regulation of iron homeostasis in cancer cells reveals a particular vulnerability to iron-depletion using iron chelators. In this review, we examine the absorption of iron from the gut; its transport, metabolism, and homeostasis in mammals; and the molecular pathways involved. Additionally, evidence for alterations in iron processing in cancer are described along with the perturbations in other biologically important transition metal ions, for example, copper(II) and zinc(II). These changes can be therapeutically manipulated by the use of novel chelators that have recently been shown to be highly effective in terms of inhibiting tumor growth.

RECENT ADVANCES

Such chelators include those of the thiosemicarbazone class that were originally thought to target only ribonucleotide reductase, but are now known to have multiple effects, including the generation of cytotoxic radicals.

CRITICAL ISSUES

Several chelators have shown marked anti-tumor activity in vivo against a variety of solid tumors. An important aspect is the toxicology and the efficacy of these agents in clinical trials.

FUTURE DIRECTIONS

As part of the process of the clinical assessment of the new chelators, an extensive toxicological assessment in multiple animal models is essential for designing appropriate dosing protocols in humans.

Changes of ferritin and CRP levels in melanoma patients treated with adjuvant interferon-α (EORTC 18952) and prognostic value on treatment outcome

Adjuvant therapy with interferon-α (IFN) only benefits a small subgroup of melanoma patients and a predictive marker selecting responders does not exist. IFN induces increased ferritin and decreased C-reactive protein (CRP) levels; however, an association with treatment effect was not studied. Serum was collected from patients participating in the European Organization for Research and Treatment of Cancer 18 952 trial comparing adjuvant treatment with IFN to observation. Serial ferritin and CRP levels were determined using enzyme-linked immunosorbent assays, before treatment and up to 24 months. Ferritin levels are influenced by sex and age; therefore ratios of serial ferritin and CRP values with corresponding pretreatment values were calculated. Cox regression model and landmark method at end of induction and 6 months were used to evaluate the association between ferritin, CRP and distant metastasis-free survival (DMFS). Baseline ferritin levels were comparable in the two treatment groups (P=0.92). However, ferritin ratios were significantly higher in IFN-treated patients (N=96) compared with untreated patients (N=21) at end of induction (mean: 2.88 vs. 0.75; P=0.0003) and at 6 months (mean: 3.18 vs. 1.02; P=0.009). In the IFN arm, higher ferritin ratios at end of induction and at 6 months were not associated with improved outcome (respectively, P=0.66 and 0.86). Concerning CRP ratios, no differences between the treatment groups, neither an association with DMFS, were observed. Administration of IFN in melanoma patients induced increase in ferritin levels but not in CRP levels. Ferritin and CRP ratios have no prognostic value regarding DMFS.

Serum ferritin: Past, present and future

BACKGROUND

Serum ferritin was discovered in the 1930s, and was developed as a clinical test in the 1970s. Many diseases are associated with iron overload or iron deficiency. Serum ferritin is widely used in diagnosing and monitoring these diseases.

SCOPE OF REVIEW

In this chapter, we discuss the role of serum ferritin in physiological and pathological processes and its use as a clinical tool.

MAJOR CONCLUSIONS

Although many aspects of the fundamental biology of serum ferritin remain surprisingly unclear, a growing number of roles have been attributed to extracellular ferritin, including newly described roles in iron delivery, angiogenesis, inflammation, immunity, signaling and cancer.

GENERAL SIGNIFICANCE

Serum ferritin remains a clinically useful tool. Further studies on the biology of this protein may provide new biological insights.

Surface-enhanced laser desorption/ionization time of flight mass spectrometry protein profiling identifies ubiquitin and ferritin light chain as prognostic biomarkers in node-negative breast cancer tumors

Novel prognostic biomarkers are imperatively needed to help direct treatment decisions by typing subgroups of node-negative breast cancer patients. The current study has used a proteomic approach of SELDI-TOF-MS screening to identify differentially cytosolic expressed proteins with a prognostic impact in 30 node-negative breast cancer patients with no relapse versus 30 patients with metastatic relapse. The data analysis took into account 73 peaks, among which 2 proved, by means of univariate Cox regression, to have a good cumulative prognostic-informative power. Repeated random sampling (n = 500) was performed to ensure the reliability of the peaks. Optimized thresholds were then computed to use both peaks as risk factors and, adding them to the St. Gallen ones, improve the prognostic classification of node-negative breast cancer patients. Identification of ubiquitin and ferritin light chain (FLC), corresponding to the two peaks of interest, was obtained using ProteinChip LDI-Qq-TOF-MS. Differential expression of the two proteins was further confirmed by Western blotting analyses and immunohistochemistry. SELDI-TOF-MS protein profiling clearly showed that a high level of cytosolic ubiquitin and/or a low level of FLC were associated with a good prognosis in breast cancer.

The design and evaluation of a novel targeted drug delivery system using cationic emulsion-antibody conjugates

In an attempt to design a targeted drug delivery system to tumors' over-expressing H-ferritin specifically recognized by a monoclonal antibody, AMB8LK, a cationic emulsion - AMB8LK conjugate was prepared. A novel cross-linker molecule bearing maleimide group was synthesized and added to cationic emulsion formulation for AMB8LK Fab' fragment covalent coupling. NMR spectroscopy confirmed the cross-linker synthesis and the preservation of the active maleimide function. SDS gel-electrophoresis results corroborated the formation of the Fab' fragment. Different densities of Fab' fragments (10-200 Fab'/oil droplet) were conjugated to emulsion droplet interface and no changes in the physico-chemical properties were observed ( approximately 120 nm size and zeta potential of approximately +30 mV). The coupling efficiency ranged from 55% to 70% and was visualized by TEM showing gold particles attached to the droplet interface. Cell culture studies demonstrated specific binding to cells as confirmed by the occurrence of the marked reduction in binding when free AMB8LK Mab was incubated before adding the AMB8LK-emulsion conjugate to the cells. The coupling of AMB8LK Fab' fragment to the cationic emulsion increased the cells uptake by 50% as compared to non-conjugated respective cationic emulsion. Appropriate conditions were, thus, identified for coupling AMB8LK Fab' fragment to cationic emulsion without altering the specificity and affinity of the Mab fragment to the tumor antigen.

Ferritin contributes to melanoma progression by modulating cell growth and sensitivity to oxidative stress

PURPOSE

Employing an in vitro model system of human melanoma progression, we previously reported ferritin light chain (L-ferritin) gene overexpression in the metastatic phenotype. Here, we attempted to characterize the role of ferritin in the biology of human melanoma and in the progression of this disease.

EXPERIMENTAL DESIGN

Starting from the LM human metastatic melanoma cell line, we engineered cell clones in which L-ferritin gene expression was down-regulated by the stable expression of a specific antisense construct. These cells were then assayed for their growth capabilities, chemoinvasive properties, and sensitivity to oxidative stress. Additionally, ferritin protein content in primary and metastatic human melanomas was determined by immunohistochemistry.

RESULTS

Artificial L-ferritin down-regulation in the LM cells strongly inhibited proliferation and chemoinvasion in vitro and cell growth in vivo. In addition, L-ferritin down-regulated cells displayed enhanced sensitivity to oxidative stress and to apoptosis. Concurrently, immunohistochemical analysis of a human melanoma tissue array revealed that ferritin expression level in metastatic lesions was significantly higher (P < 0.0001) than in primary melanomas. Furthermore, ferritin expression was constantly up-regulated in autologous lymph node melanoma metastases when compared with the respective primary tumors in a cohort of 11 patients.

CONCLUSIONS

These data suggest that high ferritin expression can enhance cell growth and improve resistance to oxidative stress in metastatic melanoma cells by interfering with their cellular antioxidant system. The potential significance of these findings deserves to be validated in a clinical setting.

Dysregulation of non-heme iron metabolism in glial brain tumors

OBJECTIVE

To study iron exchange irregularities in experimental animals and patients with glial brain tumors to ascertain the role of the 'iron component' in glial brain tumor pathogenesis.

SUBJECT AND METHODS

A suspension of A.101.08 tumor cells was implanted in the cortex of the left-brain hemisphere of rats to model experimentally induced glial brain tumor. At 7 or 14 days after implantation, blood and tissue samples from the tumor, peritumoral tissue, and brain regions were taken for analysis. Blood and plasma samples were obtained from 23 patients as well as biopsy samples taken during tumor removal surgery. Electron resonance spectroscopy was used to determine the concentrations of transferrin iron, transferrin in whole blood and in blood cells, and chelatable and stored iron in the tissues of experimental animals and patients.

RESULTS

Hypoferremia was found in rats with both small and large glial brain tumors, whereas hyperferremia was found to be a characteristic of malignant glial brain tumors in humans. We identified statistically significant increases in stored and chelatable iron concentrations in the tumor and peritumoral brain tissue compared to the blood and the adjacent brain tissue (probably normal) in both human malignant glial brain tumors and in rat experimental glial brain tumors.

CONCLUSIONS

These findings suggest that iron misregulation plays a part in glial brain tumor pathogenesis and this may provide a basis for understanding the association between glial brain tumors and epilepsy.

Structure and function of human sweat glands studied with histochemistry and cytochemistry

The basic structure and the physiological function of human sweat glands were reviewed. Histochemical and cytochemical techniques greatly contributed the elucidation of the ionic mechanism of sweat secretion. X-ray microanalysis using freeze-dried cryosections clarified the level of Na, K, and Cl in each secretory cell of the human sweat gland. Enzyme cytochemistry, immunohistochemistry and autoradiography elucidated the localization of Na,K-ATPase. These data supported the idea that human eccrine sweat is produced by the model of N-K-2Cl cotransport. Cationic colloidal gold localizes anionic sites on histological sections. Human eccrine and apocrine sweat glands showed completely different localization and enzyme sensitivity of anionic sites studied with cationic gold. Human sweat glands have many immunohistochemical markers. Some of them are specific to apocrine sweat glands, although many of them stain both eccrine and apocrine sweat glands. Histochemical techniques, especially immunohistochemistry using a confocal laser scanning microscope and in situ hybridization, will further clarify the relationship of the structure and function in human sweat glands.

Heavy chain ferritin activates regulatory T cells by induction of changes in dendritic cells

Heavy chain ferritin (H-ferritin) is a component of the iron-binding protein, ferritin. We have previously shown that H-ferritin inhibits anti-CD3-stimulated lymphocyte proliferation and that this was due to increased production of interleukin-10 (IL-10). In the present study we have shown that induction of IL-10 production was due to effects of H-ferritin on adherent antigen-presenting cells (APCs) in blood and monocyte-derived dendritic cells (MoDCs). IL-10 was produced by a subpopulation of CD4 T cells, which expressed the CD25 component of the IL-2 receptor and the CTLA-4 receptor characteristic of regulatory T cells. The changes induced in MoDCs were compared with those induced by CD40L and their significance tested by inhibition with monoclonal antibodies. These studies indicated that H-ferritin induced relatively greater expression of CD86 and B7-H1 on MoDCs and that monoclonal antibodies against their receptors, CTLA-4 and programmed death receptor-1 (PD-1), inhibited IL-10 production from the regulatory T cells. H-ferritin did not appear to induce direct production of the cytokines IL-2, IL-4, IL-6, IL-10, IL-12, or interferon-gamma from the DCs. These results are consistent with the thesis that H-ferritin induces B7-H1 and CD86 (B7-2) on APCs, which in turn induce IL-10 production from regulatory T cells. This is possibly one mechanism by which melanoma cells may induce changes in APCs in the vicinity of the tumor and result in suppression of immune responses by induction of regulatory T cells.

PLIF, a novel human ferritin subunit from placenta with immunosuppressive activity

Ferritin is a ubiquitous iron storage protein existing in multiple isoforms composed of 24 heavy and light chain subunits. We describe here a third ferritin-related subunit cloned from human placenta cDNA library and named PLIF (placental immunomodulatory ferritin). The PLIF coding region is composed of ferritin heavy chain (FTH) sequence lacking the 65 C-terminal amino acids, which are substituted with a novel 48 amino acid domain (C48). In contrast to FTH, PLIF mRNA does not include the iron response element in the 5'-untranslated region, suggesting that PLIF synthesis is not regulated by iron. The linkage between the FTH and C48 domains created a restriction site for EcoRI. PLIF protein was found to localize in syncytiotrophoblasts of placentas (8 weeks of gestation) at the fetal-maternal interface. Increased levels of PLIF transcript and protein were also detected in the breast carcinoma cell lines T47D and MCF-7 but not in the benign corresponding cell line HBL-100. In vitro, PLIF was shown to down-modulate mixed lymphocyte reactions and to inhibit the proliferation of peripheral blood mononuclear cells stimulated with OKT3. The accumulated data indicate that PLIF is an embryonic immune factor involved in down-modulating the maternal immune recognition of the embryo toward anergy. This mechanism may have been adapted by breast cancer cells over expressing PLIF.

Immunosuppressive effects of melanoma-derived heavy-chain ferritin are dependent on stimulation of IL-10 production

Cultured melanoma cells release soluble factors that influence immune responses. Screening of a cDNA library with anti-sera from a melanoma patient identified an immunoreactive plaque, which encoded heavy-chain ferritin (H-ferritin). Previous studies have drawn attention to the immunosuppressive effects of this molecule and prompted further studies on its biochemical and functional properties in human melanoma. These studies demonstrated, firstly, that H-ferritin appeared to be secreted by melanoma cells, as shown by immunoprecipitation of a 21.5 kDa band from supernatants. It was also detected in extracts of melanoma cells by Western blotting as 43 and 64 kDa dimers and trimers of the 21.5 kDa fraction. Secondly, flow-cytometric analysis of H- and light-chain ferritin (L-ferritin) expression on melanoma showed a wide variation in L-ferritin expression and consequently of the ratio of H- to L-ferritin expression. Suppression of mitogenic responses of lymphocytes to anti-CD3 showed a correlation with the ratio of H- to L-ferritin in the supernatants and was specific for H-ferritin, as shown by inhibition studies with a monoclonal antibody (MAb) against H-ferritin. Similar results were obtained with H- and L-ferritin from other sources. Suppression of mitogenic responses of lymphocytes to anti-CD3 by H-ferritin was inhibited using a MAb against IL-10, which suggested that the immunosuppressive effect of H-ferritin was mediated by IL-10. Assays of cytokine production from anti-CD3-stimulated lymphocytes showed that H-ferritin markedly increased production of IL-10 and IFN-gamma and had only slight effects on IL-2 and IL-4 production. Our results suggest that melanoma cells may be a major source of H-ferritin and that production of the latter may account for some of the immunosuppressive effects of melanoma.

Impaired Ferritin mRNA Translation in Primary Erythroid Progenitors: Shift to Iron-Dependent Regulation by the v-ErbA Oncoprotein

In immortalized cells of the erythroid lineage, the iron-regulatory protein (IRP) has been suggested to coregulate biosynthesis of the iron storage protein ferritin and the erythroid delta-aminolevulinate synthase (eALAS), a key enzyme in heme production. Under iron scarcity, IRP binds to an iron-responsive element (IRE) located in ferritin and eALAS mRNA leaders, causing a block of translation. In contrast, IRP-IRE interaction is reduced under high iron conditions, allowing efficient translation. We show here that primary chicken erythroblasts (ebls) proliferating or differentiating in culture use a drastically different regulation of iron metabolism. Independently of iron administration, ferritin H (ferH) chain mRNA translation was massively decreased, whereas eALAS transcripts remained constitutively associated with polyribosomes, indicating efficient translation. Variations in iron supply had minor but significant effects on eALAS mRNA polysome recruitment but failed to modulate IRP-affinity to the ferH-IRE in vitro. However, leukemic ebls transformed by the v-ErbA/v-ErbB–expressing avian erythroblastosis virus showed an iron-dependent reduction of IRP mRNA-binding activity, resulting in mobilization of ferH mRNA into polysomes. Hence, we analyzed a panel of ebls overexpressing v-ErbA and/or v-ErbB oncoproteins as well as the respective normal cellular homologues (c-ErbA/TR, c-ErbB/EGFR). It turned out that v-ErbA, a mutated class II nuclear hormone receptor that arrests erythroid differentiation, caused the change in ferH mRNA translation. Accordingly, inhibition of v-ErbA function in these leukemic ebls led to a switch from iron-responsive to iron-independent ferH expression.

Impaired Ferritin mRNA Translation in Primary Erythroid Progenitors: Shift to Iron-Dependent Regulation by the v-ErbA Oncoprotein

In immortalized cells of the erythroid lineage, the iron-regulatory protein (IRP) has been suggested to coregulate biosynthesis of the iron storage protein ferritin and the erythroid delta-aminolevulinate synthase (eALAS), a key enzyme in heme production. Under iron scarcity, IRP binds to an iron-responsive element (IRE) located in ferritin and eALAS mRNA leaders, causing a block of translation. In contrast, IRP-IRE interaction is reduced under high iron conditions, allowing efficient translation. We show here that primary chicken erythroblasts (ebls) proliferating or differentiating in culture use a drastically different regulation of iron metabolism. Independently of iron administration, ferritin H (ferH) chain mRNA translation was massively decreased, whereas eALAS transcripts remained constitutively associated with polyribosomes, indicating efficient translation. Variations in iron supply had minor but significant effects on eALAS mRNA polysome recruitment but failed to modulate IRP-affinity to the ferH-IRE in vitro. However, leukemic ebls transformed by the v-ErbA/v-ErbB–expressing avian erythroblastosis virus showed an iron-dependent reduction of IRP mRNA-binding activity, resulting in mobilization of ferH mRNA into polysomes. Hence, we analyzed a panel of ebls overexpressing v-ErbA and/or v-ErbB oncoproteins as well as the respective normal cellular homologues (c-ErbA/TR, c-ErbB/EGFR). It turned out that v-ErbA, a mutated class II nuclear hormone receptor that arrests erythroid differentiation, caused the change in ferH mRNA translation. Accordingly, inhibition of v-ErbA function in these leukemic ebls led to a switch from iron-responsive to iron-independent ferH expression.

Development of an automated immunoturbidimetric ferritin assay

We have developed a new procedure for turbidimetric measurement of ferritin concentration in human serum, based on latex microparticle agglutination technology. The procedure has been automated using the Falcor 300 analyzer. Carboxilated latex particles (336 nm in diameter) were covalently coupled with immunopurified F(ab')2 fragments of anti-ferritin IgG antibodies. Coated microparticles were automatically mixed with undiluted sample and the resulting absorbance due to agglutination was measured at 550 nm. The procedure generated a calibration curve with a measuring range of 0 to 558 microg/l, showing a day-to-day imprecision lower than 5.7%. The detection limit was 4 microg/l. There were no interferences from bilirubin, hemoglobin or rheumatoid factors. Turbid and lipemic samples caused an important interference which could be avoided by pretreating those samples prior to measurement. A prozone effect was provisionally obtained with ferritin concentrations over 1800 microg/l. The results suggested a hook-like effect due to a rapid microparticle precipitation in the reaction media, that could be avoided by increasing the reaction medium density by adding sucrose to the buffer, up to 150 g/l concentration. This sucrose addition resulted in a displacement of the Heidelberger curve with a prozone phenomenon occuring at concentration higher than 3000 microg/l of ferritin. Results obtained with the present procedure correlated well with those obtained by a nephelometric procedure and with those obtained by an RIA. We conclude that this latex turbidimetric immunochemical procedure is simple, rapid, has a good analytical and operational performance on the Falcor 300 analyzer and is well suited for the measurement of ferritin concentration in human serum.

Indices of iron status in continuous ambulatory peritoneal dialysis patients

Data for iron-status indices in continuous ambulatory peritoneal dialysis patients are limited. The reliability of commonly used indices for the diagnosis of iron-deficiency anemia in peritoneal dialysis patients is still unknown. To study diagnostic values of iron-status indices, including serum ferritin, transferrin saturation, reticulocyte hemoglobin content, and bone marrow-stainable iron, 21 stable anemic peritoneal dialysis patients who have been treated with erythropoietin and oral iron supplementation for more than 3 months were enrolled in this study. The mean age was 51.4 +/- 2.9 years; dialysis duration, 28.7 +/- 5.1 months; initial hemoglobin, 8.4 +/- 0.2 g/dL; erythropoietin dosage, 71 +/- 2 micro/kg/wk; serum albumin, 3.5 +/- 0.1 g/dL; intact parathyroid hormone (PTH), 233 +/- 44 ng/mL; serum ferritin, 643 +/- 135 ng/mL; transferrin saturation, 33.93% +/- 3.9%; and reticulocyte hemoglobin content, 31.6 +/- 4 pg. Bone marrow aspiration was performed in all patients to determine marrow iron content and exclude hematological disorders. All patients were treated with 1, 000 mg of intravenous ferric saccharate infusion in two divided doses more than 1 week apart. Patients who responded to the iron infusion within 3 months by increasing serum hemoglobin of greater than 1 gm/dL more than baseline were defined as being functional iron deficient before the intravenous iron infusion. Serum ferritin, transferrin saturation, and reticulocyte hemoglobin content were followed serially after iron infusion. Fifteen patients (71.4%) responded to the iron administration, indicating iron deficiency. Nine of 13 (69%) patients with the presence of bone marrow-stainable iron still responded to intravenous iron supplementation, suggesting functional iron deficiency. Absence of bone marrow-stainable iron was not a sensitive marker for the diagnosis of iron deficiency, 25% sensitivity. No single value of iron-status indices that can definitely exclude iron-deficiency anemia in peritoneal dialysis patients was found. Therefore, failure to increase hemoglobin concentration after intravenous iron administration should be shown before excluding iron-deficiency anemia as a cause of poor erythropoietic response to erythropoietin therapy.

Iron management in end-stage renal disease

One of the important components of successful anemia therapy in patients with end-stage renal disease (ESRD) treated with recombinant human erythropoietin is the maintenance of adequate available iron. To accomplish this task, iron status must be serially monitored and supplemental iron administered as required. Among nonuremic subjects, the body's iron supply is tightly conserved, and iron deficiency usually develops only when chronic blood loss occurs. In patients with ESRD, iron deficiency occurs more frequently, because of increased external losses of iron, decreased availability of the body's storage of iron, and perhaps a deficit in intestinal iron absorption. Detecting iron deficiency in these patients can be difficult because of the inaccuracy of available diagnostic tests. The goals of iron therapy in ESRD include the prevention of iron deficiency by chronically supplementing iron, and the prompt treatment of overt iron deficiency. Oral iron supplements are inexpensive and safe, but poor patient compliance and reduced intestinal absorption may limit their effectiveness. Intravenous iron supplements have a greater efficacy then oral iron, which must be weighed against the small risk of allergic reactions. We present strategies for using the various diagnostic tests and treatment modalities to effectively manage iron supply for predialysis, hemodialysis, and peritoneal dialysis patients.

Extremely elevated serum ferritin levels in a university hospital: associated diseases and clinical significance

PURPOSE

To establish the frequency with which serum ferritin levels > or = 1,000 ng/mL occur in a general hospital population, and to determine the clinical significance of this finding.

PATIENTS AND METHODS

All serum ferritin determinations performed between June 1992 and July 1993 at the University of Cincinnati Medical Center were reviewed and patients with serum ferritin levels > or = 1,000 ng/mL identified. The medical records of these patients were then reviewed.

RESULTS

Of 1,826 serum ferritin determinations performed during the study period, 122 (6.7%) were > or = 1,000 ng/mL. Associated clinical syndromes found in the 95 patients with serum ferritin > or = 1,000 ng/mL included liver disease (20.0%), renal disease (17.9%), malignant disease (17.9%), human immunodeficiency virus (HIV) infection (16.8%), non-HIV systemic infections (15.8%), chronic transfusions (10.5%), and sickle cell syndromes (10.5%). No syndrome usually associated with extreme serum ferritin elevations was identified in 8.4% of patients, and 16.8% of the patients fell into more than one category. The highest mean serum ferritin levels occurred in the chronically transfused and sickle cell groups. Concomitant serum transferrin saturation values were determined with 82 (86.3%) of the elevated serum ferritin levels and did not correlate well with them. The highest mean transferrin saturation levels occurred in the liver disease group. Transferrin saturation > or = 50%, suggestive of iron overload, was significantly more frequent in the liver disease group (P = 0.002); and saturation < or = 15%, suggestive of iron-deficient erythropoiesis, was significantly more frequent in the HIV group (P = 0.001).

CONCLUSION

Outside the setting of clinical syndromes associated with iron overload (liver disease, transfusions, sickle cell syndromes), serum ferritin levels > or = 1,000 ng/mL serve as a nonspecific marker for a variety of significant disorders, including infectious and neoplastic diseases. Further study of the regulation of ferritin production may provide insight into the pathogenesis of disorders associated with extreme serum ferritin elevations.

Ferritin levels in pediatric HIV-1 infection

Ferritin is an acute phase protein which is often elevated in acute and chronic inflammation, as well as in neoplastic disease. In adults with human immunodeficiency virus (HIV) infection, elevated serum ferritin levels indicate advanced or progressive disease. In the present study, ferritin levels were evaluated in 88 HIV-infected children. Ferritin levels greater than 100 ng/ml were found in 93% of patients with advanced disease. Increasing levels always accompanied or closely preceded rapid disease progression. Serum ferritin levels may prove to be a useful marker to monitor disease progression and therapeutic efficacy in HIV-infected children.

Clinical significance of serum iron and ferritin in patients with colorectal cancer

To clarify the significance of serum iron and ferritin as indicators of iron loss caused by continuous bleeding, and, thus, to determine their value as markers of colorectal cancer, values for the two were compared in male patients with early and advanced colorectal cancer and age-matched male controls. The mean value of serum iron levels in patients with advanced colorectal cancer was significantly decreased compared with values in patients with early colorectal cancer and controls, 50.5 +/- 38.6 micrograms/dl vs 93.0 +/- 32.1 micrograms/dl and 107.1 +/- 32.9 micrograms/dl, respectively (p < 0.001). The mean value of serum ferritin levels in patients with early and advanced colorectal cancer was also significantly decreased compared with controls, 80.5 +/- 35.0 ng/ml (p < 0.01) and 48.8 +/- 72.8 ng/ml (p < 0.001), respectively, vs 117.1 +/- 46.8 ng/ml. However, there was no significant difference between mean serum iron levels in patients with early colorectal cancer and controls. Eighteen (78.3%) of the 23 patients with advanced colorectal cancer and 3 (16.7%) of the 18 patients with early colorectal cancer had serum iron levels below 85 micrograms/dl and serum ferritin levels below 60 ng/ml. Levels of both serum iron and ferritin, without clinically evident anemia, are useful indicators of advanced colorectal cancer.

Cytosol and serum ferritin in breast carcinoma

This study was undertaken to determine tissue and serum ferritin levels in different stages of breast carcinoma. Eighty-nine cases have been evaluated, the groups investigated being breast carcinoma, benign breast disease and healthy controls. Ferritin levels in both the sera and the tissue cytosols were measured by an enzyme immunoassay method, while total proteins were assayed by Lowry's procedure and the ferritin concentrations given in ng ferritin/mg cytosol protein. No significant difference has been determined for serum ferritin between any of the groups studied, while the tissue cytosol ferritins were found to be 91.6 +/- 50.9, 565.0 +/- 48.3, 142.7 +/- 93.3, 683.3 +/- 212.9 and 655.5 +/- 100.4 ng/mg cytosol protein for the benign, malign (global), malign (stage I), malign (stage II) and malign (stage III) groups, respectively. The differences between the malign groups and the benign group were found to be highly significant (P < 0.001) except for the stage I subgroup, which was fairly significant (P < 0.05). A sensitivity of 90% was evaluated for tissue cytosol ferritin in breast carcinoma, the 'intra-patient' sensitivity being 100%. In conclusion, we state that tissue ferritin is more valuable than serum ferritin as a tumour marker of diagnosis for breast carcinoma.

Glycosylated serum ferritin in patients with hematological malignancies before and after bone marrow transplantation

Glycosylated and total serum ferritin levels were monitored in patients with acute leukemia and lymphoma undergoing bone marrow transplantation (BMT). Serum ferritin was high in relapsing patients and normal in most patients in complete remission (CR). In patients with an uncomplicated course, levels of ferritin increased during the first month after BMT with subsequent decrease. Three patients with lymphoma and five with acute leukemia had high serum ferritin levels despite achieving apparent complete hematological remission which was of short duration. The results were compared with groups of lymphoma patients at presentation and during remission and with healthy normal controls. In all the lymphoma patients and in 3 of the 5 leukemia patients the percent of ferritin glycosylation was normal at CR. It was low at the time of diagnosis in all patients. Thus, the percent glycosylation proved a more reliable marker for clinical remission than total serum ferritin. During follow up after BMT in uncomplicated cases, the percent of glycosylated ferritin returned to normal levels earlier than the total serum ferritin. These findings indicate that the evaluation of the amount of glycosylated ferritin may provide useful information in hematological patients in whom there is a discrepancy between high serum ferritin levels and the clinical condition.

Isolation of cDNA clones corresponding to genes differentially expressed in two colon-carcinoma cell lines differing by their tumorigenicity

In an effort to isolate genes involved in the progression of colonic cells leading to a carcinoma, we used as a model 2 rat colon-carcinoma cell lines selected from the same tumor, differing by their tumorigenicity. When soluble, Triton-X-100 extracted, or cytoskeletal proteins from the progressive PROb cells and the regressive REGb cells were analyzed by SDS-PAGE, minor differences were seen. Furthermore, mRNA-cDNA hybridization analyses showed extensive homology between the 2 mRNA populations. Thus, the homology between the 2 clones is high at both the protein and the mRNA levels. A PROb cDNA library was hybridized with 32P-cDNA synthesized from PROb or REGb mRNA. The clones giving a stronger signal when hybridized with the homologous PROb probe were isolated. The specificity of each clone was confirmed by RNA blotting. Most of the positive clones showed a 2- to 3-fold higher expression in PROb cells when compared with REGb cells. One clone (J 13) corresponded to an mRNA 7- to 10-fold more abundant in PROb cells, and was further studied. No gene amplification was detected by Southern blot analysis, indicating that the difference in mRNA content was most likely due to an increased transcription of this gene in PROb cells. Sequencing of the cDNA showed high homology with the rat ferritin light sub-unit. Over-expression of ferritin in PROb cells as compared with REGb cells was confirmed at the protein level using specific antibodies.

Automated quantitative nephelometric latex immunoassay for determining ferritin in human serum

We describe a rapid and sensitive latex nephelometric immunoassay for quantifying ferritin in human serum. This latex immunoassay procedure uses commercially available ready-for-use reagents [Tina-Quant (a) Ferritin, Boehringer Mannheim] that have a long shelf life. The assay consists of incubating the diluted serum sample (5-fold) for 12 min at room temperature with latex particles covalently coated with anti-ferritin antibodies, and then quantifying the change of light-scatter produced. The assay is fully automated on the Behring nephelometer analyzer with a sampling rate of 150 samples/hour. The method has an analytical range of 3 to 260 micrograms/l. Maximal intra- and inter-assay CVs were 4.0 and 6.2%, respectively. Analytical recoveries ranged from 91.3 to 103.6%. Assay detection limit was less than 3 micrograms/l. Linearity of the test is given throughout the measuring range. There was no interference from bilirubin (up to 340 mumol/l), haemoglobin (up to 7 g/l), or rheumatoid factor (up to 1,100 IU/ml). Turbid and lipemic samples interfere. This interference may be avoided by pretreating these samples prior to assay. Results correlated well with those obtained by an automated ELISA test (r = 0.995) and with those of two commercial RIA methods (r greater than 0.97). This latex nephelometric procedure is a convenient method and represents an interesting alternative to other immunoassays for measuring ferritin in human serum.