Combinational antibody detection approach increases the clinical validity of colorectal cancer screening.

BACKGROUND: At different stages of the disease, biomarkers can help to determine disease progression and recurrence and provide a personalized indicator of therapeutic effectiveness. The serological identification of antigens by recombinant cDNA expression cloning (SEREX) has identified five SEREX antigens. RESULTS: Compared with healthy donors, anti-FIRΔexon2 and anti-SOHLH antibodies (Abs) in the sera of patients with colorectal cancer (CRC) were markedly higher. Furthermore, no correlation was noted between five SEREX antigens and the three tumor markers (CEA, CA19-9, and anti-p53 Abs), indicating that anti-FIRΔexon2 Abs are an independent candidate marker for patients with CRC. Generally, the levels of anti-FIRΔexon2 Abs combined with clinically available tumor markers were determined to be significantly higher compared with CEA, CA19-9. Moreover, in early-stage CRC, the levels of anti-FIRΔexon2 Abs combined with existing tumor markers were higher than those of CEA, CA19-9. CONCLUSION: Due to the highly heterogeneous nature of CRC, a single tumor marker is unlikely to become a standalone diagnostic test due to its commonly insufficient sensitivity and/or specificity. Using a combination antibody detection approach of tumor markers for CRC diagnosis has the potential to be an effective approach. Therefore, the use of serum protein biomarker candidates holds promise for the development of inexpensive, noninvasive, and inexpensive tests for the detection of CRC.

Anti-FIRΔexon2 autoantibody as a novel indicator for better overall survival in gastric cancer.

There is no clinically available biomarker for efficiently indicating the overall survival or therapy response of gastric cancer (GC). The autoantibodies (Abs) in the sera of anti-far-upstream element-binding protein-interacting repressor-lacking exon2 (FIRΔexon2), anti-sorting nexin 15, and anti-spermatogenesis and oogenesis-specific basic helix-loop-helix 1 were markedly higher in GC patients than in healthy donors (HDs). These Abs were identified by large-scale serological identification of antigens by recombinant cDNA expression cloning screenings and their expression levels were evaluated by amplified luminescence proximity homogeneous assay. In particular, compared with age-matched HDs, the level of anti-FIRΔexon2 Abs in GC patients was significantly higher (P < .001). The Spearman's rank correlation analysis between anti-FIRΔexon2 Abs and clinically available tumor markers such as carcinoembryonic antigen (CEA) was statistically insignificant, indicating that FIRΔexon2 Abs is an independent biomarker. We performed receiver-operating curve analysis to evaluate the anti-FIRΔexon2 Ab as a candidate biomarker with CEA and carbohydrate antigen 19-9 (CA19-9). The overall survival of GC patients with high anti-FIRΔexon2 Abs titer was significantly favorable (P = .04) than that of GC patients who were below detection level of anti-FIRΔexon2 Abs. However, clinical stages were not apparently correlated with the levels of anti-FIRΔexon2 Ab, CEA, and CA19-9. In conclusion, anti-FIRΔexon2 Abs detected in GC patients is a potential biomarker for monitoring a better prognosis. Hence, anti-FIRΔexon2 Abs is a promising biomarker for indicating better overall survival of gastric cancer patients.

[Biochemical-Immunological Examination].

Abnormal laboratory values are often attributable to errors in pre-test processes, such as those in blood collection or sample treatment. Although these errors occur frequently, only a small percentage of them are detected, possibly resulting in misdiagnoses. In addition, when performing blood collection or sample treatment, not only doctors and nurses, but also medical technologists, who are conversant with laboratory tests, may generate abnormal values due to incorrect recognition or carelessness. On the other hand, although it is impossible to identify all abnormal values caused by pre-test errors in laboratories, the nonidentification of these errors will lead to iatrogenically abnormal values. Therefore, staff members conducting analyses are required to be familiar with many cases of abnormal values associated with blood collection, and to have skills to consider errors that may be responsible for the abnormal values identified. In this report, I present pre-test errors causing abnormal values, and measures against these errors.

Change in albumin measurement method affects diagnosis of nephrotic syndrome.

BACKGROUND: Although serum albumin levels (sALB) have been quantified by the dye-binding method with bro- mocresol green (BCG) or bromocresol purple (BCP) on a routine basis, accurate measurement of sALB with these methods is difficult. The modified BCP method is highly specific to albumin without being affected by sample preservation to enable stable and accurate quantification of albumin concentrations. A change in the albumin measurement method may alter the diagnosis of nephrotic syndrome. METHODS: sALB was measured in 295 patients including 98 patients with chronic renal disease by the modified BCP method, BCG method, and immunonephelometry as the gold standard. RESULTS: sALB measured by the modified BCP method was well correlated with levels measured by immunonephelometry. sALB obtained by the BCG method was significantly higher than the levels measured by the modified BCP method (p < 0.001, Student's t-test). This tendency was more evident in patients with chronic renal disease than other patients. When the threshold value of sALB for the diagnosis criteria of nephrotic syndrome (≤ 25 g/L) and a high risk of thrombosis (≤ 20 g/L) in nephrotic syndrome was based on the BCG method, the revised criteria in the modified BCP method would be ≤ 20.5 and ≤ 14.9 g/L, respectively. CONCLUSIONS: Overestimation of sALB by the BCG method affected diagnosis of nephrotic syndrome. The method by which sALB is measured should be specified in both clinical and research settings in nephrology.

Development of a plasma maltose assay method as a screening test for upper gastrointestinal disorders.

BACKGROUND AND OBJECTIVE: The disaccharide loading test is a method to assess gastric mucosal damage. Since Trelan-G75, which is used for the sugar tolerance test, contains disaccharide maltose, if maltose is detected at a high sensitivity in the sample blood used in the sugar tolerance test, screening for upper gastrointestinal mucosal damage can be made simultaneously with the sugar tolerance test for the diagnosis of diabetes. METHODS: Glucose-6-phosphate is generated by treating maltose with maltose phosphorylase, ß-phosphoglucomutase, and glucose-1,6-bisphosphate. Then, change in the absorbance at 405 nm is measured by the enzymatic cycling method using Thio-NADP, ß-NADPH, and Glucose-6-phosphate dehydrogenase. After evaluating the optimal condition for this method, it is mounted on an automatic biochemical analyzer, and samples after the sugar tolerance test were assayed. RESULTS: Regarding the performance of this method, the repeatability was 10-50 µmol/L with a CV of ≤1.1%. Concerning the assay range, a curve passing the origin with a range of linearity up to 120 µmol/L was obtained. No effect of dyes or sugars in the blood was noted. As a result of application to patients with gastric mucosal disorders (those who had a health checkup), significant differences were observed depending on the stage of atrophic gastritis. DISCUSSION: This method has a high sensitivity and a high precision and can be used for high-speed analysis on an automatic analyzer. It has the potential to be used as a screening test for gastric mucosal damage.

Patent blue interferes with the measurement of lipemia index in a patient with sentinel lymph node.

Lipids interfere with absorbance measurements conducted using colorimetric methods. To monitor lipemia, some systems measure absorbance using an analyzer. This report describes a novel case of interference with the lipemia index without lipemia. A 64-year-old woman with giant basal cell carcinoma underwent resection and sentinel lymph node biopsy. The patient had been subcutaneously injected with patent blue during sentinel lymph node resection. After surgery, her serum and urine were yellow-green, and the lipemia index, calculated by measuring absorbance at 658 nm (main wavelength) and 694 nm (secondary wavelength) using a JCA-BM8040 chemistry analyzer, was high. The absorbance spectrum of the patient's serum and patent blue solution were compared to determine the cause of the high lipemia index. The patient's serum and the patent blue solution showed absorption at wavelengths between 540 and 698 nm. Moreover, the absorbance was concentration-dependent for patent blue. These results thus indicated that the patient's serum contained patent blue. Here, we report a case wherein patent blue affected the lipemia index. Thus, it must be noted that patent blue injection may yield inaccurate results when evaluating lipemia index.

Combined proteomic analysis of liver tissue and serum in chronically alcohol-fed rats.

BACKGROUND: Proteomic approaches may provide new insights into pathological conditions associated with alcoholism. The aim of this study was to conduct a proteomic analysis of liver tissue and serum in chronically alcohol-fed rats using agarose 2-dimensional gel electrophoresis (2-DE) and 3-step serum proteome analysis. METHODS: A total of 12 rats were pair-fed nutritionally adequate liquid diet containing ethanol as 36% of the total energy or an isocaloric control diet for 2 months. Rat liver homogenates and cytosol fractions were subjected to agarose 2-DE. Serum samples were subjected to 3-step serum proteome analysis involving immunodepletion of abundant proteins followed by fractionation using reverse-phase high-performance liquid chromatography and 1-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Candidate proteins were digested with trypsin and identified using mass spectrometry. Observed differences in protein expression levels were confirmed using Western blotting. RESULTS: A total of 46 protein spots were found to be differentially expressed in the liver homogenates and cytosol fractions of alcohol-fed rats relative to pair-fed controls. The most notable change was down-regulation of a 29-kDa protein, which was subsequently identified as carbonic anhydrase III (CA III). Down-regulation of this protein in alcohol-fed rats was confirmed by Western blotting. The messenger RNA level of CA III was decreased as well. In rat serum, a total of 41 proteins were differentially expressed. Of these proteins, only betaine-homocysteine methyltransferase (BHMT) was also found to be differentially expressed in the liver. CONCLUSIONS: A combined proteomic analysis of liver tissue and serum in chronically alcohol-fed rats revealed that the expression of CA III is significantly down-regulated in the liver of alcohol-fed rats. Our results also showed that BHMT expression is up-regulated in both the liver and serum of alcohol-fed rats.

[Usefulness of the standardized serum cystatin C reagent in evaluation of renal function].

Serum cystatin C (sCysC) is valuable to evaluate the renal functions in various clinically studies. Since the reagents to detect sCysC are different among institutes or hospitals, the accidental error due to the difference of reagents is not negligible. That is why sCysC is sometimes difficult to use or interpret for patient as estimated Glomerular filtration rate (eGFR) that is one of the most popular factors to evaluate renal function. Recently, the international reference standard is gradually accepted as standardization of chemical measurement of sCysC in Japan. Japan Society of Clinical Chemistry has reported the utilities for sCysC measurement standardization in 2010. In this study, we examined the usefulness of the standardization of sCysC reagent in Chiba University Hospital. Our study indicated that the clinical usefulness of eGFR calculated by sCysC. As results, eGFR from serum creatinine (sCr) was relatively high in patients with reduced muscle mass, such as old-age patients with wheelchair and prolonged hospitalization. On the other hand, eGFR from sCysC was high in patients with hypothyroidism. Together, eGFR calculated by sCysC is clinically available for the patients with reduced muscle mass could be underestimated. Further studies are required to evaluate the validity of standardization of sCysC measurement and find the dissociation among eGFR, sCysC and sCr depending in the renal disease or pathogenesis.

IgG4-IgE complex interferes with measurement of IgE concentration.

BACKGROUND AND AIMS: Patients with immunoglobulin G4 (IgG4)-related disease (IgG4-RD) have elevated immunoglobulin E (IgE) concentration compared to that in healthy individuals, which suggests the occurrence of IgE-mediated allergic reactions. We have previously shown that IgG4 and IgE form a complex in some patients with IgG4-RD. However, it is currently unknown whether and how the presence of the IgG4-IgE complex affects IgE concentration measurements by different assays. MATERIALS AND METHODS: Twenty patients with confirmed presence or absence of IgG4-IgE complex were evaluated. We compared IgE concentrations measured by ST AIA-PACK IgE II (AIA-PACK), Elecsys IgE II Immunoassay (Elecsys), and Iatroace IgE (Iatroace) and evaluated to what extent the IgG4-IgE complex interfered with these measurements. RESULTS: In patients with the IgG4-IgE complex, IgE concentrations measured using Iatroace were significantly lower than those measured using Elecsys and tended to be lower than those measured using AIA-PACK. IgE concentrations determined by Iatroace were significantly different in patients with and without the IgG4-IgE complex, whereas no significant differences between these groups were detected when IgE concentrations were measured by AIA-PACK or Elecsys. CONCLUSION: The formation of the IgG4-IgE complex underestimates measured IgE concentrations depending on the method used. Therefore, caution should be exercised when selecting a specific IgE assay for patients with IgG4-RD.

Frequencies of Anti-Troponin I vs Anti-Troponin T Autoantibodies and Degrees of Interference on Troponin Assays.

OBJECTIVE: Presence of autoantibodies against troponin I (cTnI) or T (cTnT) has been reported to interfere with troponin assays. However, the extent of the interference with the measurement has not been explored sufficiently. The aims of this study were to examine the frequencies of autoantibodies against troponin I and troponin T and how much these antibodies would affect the measurement. METHODS: The study comprised 52 subjects who visited Hokkaido University Hospital with suspected ischemic heart diseases. To evaluate the presence of autoantibodies, we calculated the recoveries of cTnI or cTnT after immunoglobulin G depletion, and the distributions of peaks reactive with cTnI or cTnT by high-performance liquid chromatography were examined. RESULTS: Autoantibodies against cTnI and cTnT were identified in 8 subjects (15.4%) and 1 subject (1.9%), respectively. Although the greatest difference between cTnI and cTnT was 32-fold, the distributions of cTnI-to-cTnT ratios in groups with and without anti-cTnI were not statistically different. CONCLUSION: Autoantibodies against cTnI were more frequent by several fold than those against cTnT. Their presence did not significantly expand the discrepancy between cTnI and cTnT assays.

UTX inactivation in germinal center B cells promotes the development of multiple myeloma with extramedullary disease.

UTX/KDM6A, a histone H3K27 demethylase and a key component of the COMPASS complex, is frequently lost or mutated in cancer; however, its tumor suppressor function remains largely uncharacterized in multiple myeloma (MM). Here, we show that the conditional deletion of the X-linked Utx in germinal center (GC) derived cells collaborates with the activating BrafV600E mutation and promotes induction of lethal GC/post-GC B cell malignancies with MM-like plasma cell neoplasms being the most frequent. Mice that developed MM-like neoplasms showed expansion of clonal plasma cells in the bone marrow and extramedullary organs, serum M proteins, and anemia. Add-back of either wild-type UTX or a series of mutants revealed that cIDR domain, that forms phase-separated liquid condensates, is largely responsible for the catalytic activity-independent tumor suppressor function of UTX in MM cells. Utx loss in concert with BrafV600E only slightly induced MM-like profiles of transcriptome, chromatin accessibility, and H3K27 acetylation, however, it allowed plasma cells to gradually undergo full transformation through activation of transcriptional networks specific to MM that induce high levels of Myc expression. Our results reveal a tumor suppressor function of UTX in MM and implicate its insufficiency in the transcriptional reprogramming of plasma cells in the pathogenesis of MM.

Serum anti-Ku86 is a potential biomarker for early detection of hepatitis C virus-related hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is one of the most common cancers worldwide and the third most common cause of cancer-related death. Imaging studies including ultrasound and computed tomography are recommended for early detection of HCC, but they are operator dependent, costly and involve radiation. Therefore, there is a need for simple and sensitive serum markers for the early detection of hepatocellular carcinoma (HCC). In our recent proteomic studies, a number of proteins overexpressed in HCC tissues were identified. We thought if the serum autoantibodies to these overexpressed proteins were detectable in HCC patients. Of these proteins, we focused on Ku86, a nuclear protein involved in multiple biological processes and aimed to assess the diagnostic value of serum anti-Ku86 in the early detection of HCC. Serum samples were obtained prior to treatment from 58 consecutive patients with early or relatively early hepatitis C virus (HCV)-related HCC and 137 patients with HCV-related liver cirrhosis without evidence of HCC. Enzyme immunoassays were used to measure serum levels of autoantibodies. Serum levels of anti-Ku86 antibodies were significantly elevated in HCC patients compared to those in liver cirrhosis patients (0.41±0.28 vs. 0.18±0.08Abs at 450nm, P<0001). Setting the cut-off level to give 90% specificity, anti-Ku86 was positive in 60.7% of stage I solitary tumor <2cm in diameter, whereas the sensitivities of alpha-fetoprotein (AFP) and protein induced by vitamin K absence or antagonist II (PIVKA-II) were 17.8% and 21.4%, respectively. The results of ROC analyses indicated the better performance of anti-Ku86 for early detection of HCC. Serum anti-Ku86 levels decreased after surgical resection of the tumors in the 12 HCC cases tested, Elevation of anti-Ku86 in solid tumors other than liver was minimal. Serum anti-Ku86 is a potential biomarker for early detection of HCV-related HCC. Further studies in a larger number of HCC patients with various etiologies are needed to further evaluate the diagnostic and pathophysiological roles of elevation of serum anti-Ku86 in early HCC.

Serum cystatin C as a marker for early detection of chronic kidney disease and grade 2 nephropathy in Japanese patients with type 2 diabetes.

BACKGROUND: Diabetic nephropathy (DN) is a significant cause of hemodialysis, and its early detection is extremely important to prevent or delay end-stage renal disease. The significance of the renal function marker serum cystatin C (sCysC) and its relationship with glomerular filtration rate in chronic kidney disease (CKD) and DN in Japanese patients with type 2 diabetes remains uncertain. In this study, we examined the effectiveness of sCysC as a marker of early DN and CKD in Japanese subjects. METHODS: A total of 325 Japanese patients with type 2 diabetes and 88 healthy subjects were studied retrospectively. sCysC concentration (mg/L) was determined by a latex turbidmetric immunoassay using a BioMajesty 8040 analyzer. The renal function of the diabetic patients was evaluated using the albumin-creatinine ratio (ACR) and Kidney Disease Outcome Quality Initiative-Kidney Disease Improving Global Outcomes (K/DOQI-KDIGO) classification. RESULTS: There was a significant increase in sCysC but not in serum creatinine (sCr) or serum ß2-microglobulin (sß2M) in patients with grade 2 DN (ACR 30-300 mg/g) compared to grade 1 patients. Receiver operating characteristic analysis in grade 2 and 3 DN patients showed that sCysC had superior sensitivity and specificity than sCr and sß2M for early detection of DN. In addition, sCysC showed particularly high sensitivity and specificity in DN patients with stage 2 CKD. CONCLUSIONS: sCysC was effective for detection of grade 2 DN and would be especially useful for screening stage 2 CKD patients (K/DOQI-KDIGO).

IgG4-IgE complex in a patient with IgG4-related disease.

BACKGROUND: IgE concentrations are occasionally elevated in patients with IgG4-related disease (IgG4-RD). In this report, we describe a novel case of IgG4-RD in which IgE concentrations were discordant between measuring reagents. CASE: An 81-year-old man was diagnosed with IgG4-RD and histological autoimmune pancreatitis, which ensued without treatment. The IgE concentrations measured using Elecsys IgE II Immunoassay and Iatroace IgE were 1287.0 IU/mL and 60.9 IU/mL, respectively. IgG4 concentration was 675 mg/dL. METHODS: To identify IgG and IgG4 directly bound to IgE, purification using protein G and anti-IgG4 antibody-conjugated matrixes and size-exclusion high-performance liquid chromatography (HPLC) were performed. RESULTS: In purification analysis, the IgE concentration of the flow-through and bound fractions were 6.8 IU/mL (10.8%) and 56.2 IU/mL (89.2%) for IgG purification and 6.8 IU/mL (12.2%) and 49.0 IU/mL (87.8%) for IgG4 purification. IgE was eluted as a single peak (640 kDa) using size-exclusion HPLC. In the elution pattern of IgG4, a minor peak (640 kDa) and a major peak (170 kDa) were observed. These results indicate that IgG4 binds to IgE and forms a complex, resulting in a discrepancy between reagents. CONCLUSIONS: In this report, we present an IgG4-IgE complex in a patient with IgG4-RD, which affected the discrepancy in IgE concentrations between IgE reagents. This report points to the significance of increased IgE production in IgG4-RD.

IgG4-IgE complex in patients with IgG4-related disease.

BACKGROUND: IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disease characterized by high IgE levels; however, the physiological significance of elevated IgE levels in patients with IgG4-RD is unclear. Previously, we reported the formation of IgG4-IgE complex in IgG4-RD patients with elevated IgE levels. In this study, we examined the frequency of this complex formation and its relationship with the clinical features in IgG4-RD patients. METHODS: The IgG4-IgE complex was evaluated in 33 and 17 patients with and without IgG4-RD, respectively. The IgG4-IgE complex was evaluated by performing the immunoadsorption of IgG4 using anti-IgG4 antibody-conjugated matrices. RESULTS: The frequency of IgG4-IgE complex formation in patients with IgG4-RD was significantly higher than that in those without IgG4-RD (21.2% vs. 0%). No significant differences were observed between the groups in terms of clinical characteristics and laboratory data. However, the IgG4-IgE complex-positive group had a significantly higher frequency of pancreatic lesions (85.7% vs. 42.3%) and a significantly lower rate of retroperitoneal fiber/periarterial lesions (0% vs. 38.5%) than the IgG4-IgE complex-negative group. CONCLUSION: The IgG4-IgE complex was found only in patients with IgG4-RD which may provide some clues to the pathogenesis and etiology of IgG4-RD.

Reducing the incidence of pseudohyperkalemia by avoiding making a fist during phlebotomy: a quality improvement report.

BACKGROUND: Pseudohyperkalemia is uncommon, but important. Local release of potassium caused by contraction of the forearm muscles from a tightly clenched fist or repeated fist clenching during phlebotomy is a recognized cause of pseudohyperkalemia. We investigated the use of a standard protocol to avoid fist clenching during phlebotomy. STUDY DESIGN: Quality improvement report. SETTING & PARTICIPANTS: In 7 healthy volunteers, 10 blood samples were collected over 10-second intervals after 20 repeated fist clenching and unclenching movements. In 86 healthy volunteers, 3 blood samples were collected with and without prior fist clenching. Between September 1, 2006, and June 30, 2007, peripheral venous blood samples were collected from 73,846 outpatients at Chiba University Hospital without a protocol to avoid fist clenching. Between July 1, 2007, and March 31, 2009, blood samples were collected from 171,053 outpatients using the protocol. QUALITY IMPROVEMENT PLAN: After July 1, 2007, blood samples were collected from the basilic or cephalic vein without making a fist or by making a fist using minimal gripping strength. Also, when multiple specimens were obtained from 1 patient, the specimen for measuring serum electrolytes was obtained after the other specimens. OUTCOMES & MEASUREMENTS: Pseudohyperkalemia, defined as unexplained serum potassium level ≥6.5 mmol/L. RESULTS: In the 7 volunteers, the decrease in serum potassium levels after cessation of fist clenching ranged from 8.4%-25.9%. In the 86 volunteers, the percentage with a decrease in serum potassium level ≥0.2 mmol/L between the first and third samples was 25.6% versus 6.7% with or without prior fist clenching, respectively. In clinical practice, we observed 8 cases of pseudohyperkalemia before implementing the protocol (0.0081%) and 1 case (0.00058%) after implementing the protocol (P = 0.001). LIMITATIONS: Causes of hyperkalemia before using precautions were assessed using retrospective analyses. CONCLUSIONS: Avoiding fist clenching during phlebotomy and not using the first specimen for electrolyte measurements when obtaining multiple specimens from a single patient can reduce the occurrence of pseudohyperkalemia.

A highly sensitive and rapid enzymatic method using a biochemical automated analyzer to detect inorganic pyrophosphate generated by nucleic acid sequence-based amplification.

BACKGROUND AND AIMS: Polymerase chain reaction-based techniques require expensive equipment for fluorescence detection of the products. However, the measurement of inorganic pyrophosphate (PPi) released during DNA synthesis can be used to quantify target genes without such equipment. Here, we devised a high-sensitivity enzymatic assay for detection of PPi. MATERIALS AND METHODS: In our assay method, PPi was converted to hypoxanthine by hypoxanthine phosphoribosyl transferase. Xanthine dehydrogenase converted the hypoxanthine to uric acid and yielded two molecules of NADH, which in turn reduced Fe3+ to Fe2+ (mediated by 1-methoxy-5-ethylphenazinium ethylsulfate). 2-Nitroso-5-(N-propyl-N-sulfopropylamino) phenol chelated the Fe2+, which resulted in an intensely colored product that could be measured using a biochemical automated analyzer. RESULTS: The assay was able to detect PPi within 10 min. It was linear between 0 and 10 µmol/L PPi, and intra-run and inter-run coefficients of variation were 1%-2%. Other validation tests with a biochemical automated analyzer were satisfactory. The assay could potentially be used to directly quantify samples after isothermal nucleic acid sequence-based amplification of a target gene. CONCLUSION: The method developed here for detection of PPi can be used to measure nucleic acid biomarkers in biological samples in clinical practice using a high-throughput biochemical automated analyzer.

Identification of novel immunohistochemical tumor markers for primary hepatocellular carcinoma; clathrin heavy chain and formiminotransferase cyclodeaminase.

UNLABELLED: Early diagnosis of hepatocellular carcinoma (HCC) greatly improves its prognosis. However, the distinction between benign and malignant tumors is often difficult, and novel immunohistochemical markers are necessary. Using agarose two-dimensional fluorescence difference gel electrophoresis, we analyzed HCC tissues from 10 patients. The fluorescence volumes of 48 spots increased and 79 spots decreased in tumor tissues compared with adjacent nontumor tissue, and 83 proteins were identified by mass spectrometry. Immunoblot confirmed that the expression of clathrin heavy chain (CHC) and Ku86 significantly increased, whereas formiminotransferase cyclodeaminase (FTCD), rhodanese, and vinculin decreased in tumor. The protein expression in tumor and nontumor tissues was further evaluated by immunostaining. Interestingly, CHC and FTCD expression was strikingly different between tumor and nontumor tissues. The sensitivity and specificity of individual markers or a combination for the detection of HCC were 51.8% and 95.6% for CHC, 61.4% and 98.5% for FTCD, and 80.7% and 94.1% for CHC+FTCD, respectively. Strikingly, the sensitivity and specificity increased to 86.7% and 95.6% when glypican-3, another potential biomarker for HCC, was used with FTCD. Moreover, CHC and FTCD were useful to distinguish early HCC from benign tumors such as regenerative nodule or focal nodular hyperplasia, because the sensitivity and specificity of the markers are 41.2% and 77.8% for CHC, 44.4% and 80.0% for FTCD, which is comparable with those of glypican-3 (33.3% and 100%). The sensitivity significantly increased by combination of these markers, 72.2% for CHC+FTCD, and 61.1% for CHC+glypican-3 and FTCD+glypican-3, as 44.4% of glypican-3 negative early HCC were able to be detected by either CHC or FTCD staining. CONCLUSION: Immunostaining of CHC and FTCD could make substantial contributions to the early diagnosis of HCC.