Elevated serum levels of sialyl Lewis X (sLeX) and inflammatory mediators in patients with breast cancer.

PURPOSE: The carbohydrate sialyl LewisX (sLeX) mediates cell adhesion, is critical in the normal function of immune cells, and is frequently over-expressed on cancer cells. We assessed the association, differential levels, and prognostic value of sLeX and inflammatory cytokines/chemokines in breast cancer sera. METHODS: We retrospectively measured sLeX and a panel of cytokines/chemokines in the sera of 26 non-invasive ductal carcinoma in situ (DCIS), 154 invasive non-metastatic breast cancer (non-MBC), 63 metastatic breast cancer (MBC) patients, and 43 healthy controls. Differences in sLeX and inflammatory cytokines among and between patient groups and healthy controls were assessed with nonparametric tests and we performed survival analysis for the prognostic potential of sLeX using a cut-off of 8 U/mL as previously defined. RESULTS: Median serum sLeX was significantly higher than controls for invasive breast cancer patients (MBC and non-MBC) but not DCIS. In univariate analysis, we confirmed patients with serum sLeX > 8 U/mL have a significantly shorter progression-free survival (PFS) (P = 0.0074) and overall survival (OS (P = 0.0003). Similarly, patients with high serum MCP-1 and IP-10 had shorter OS (P = 0.001 and P < 0.001, respectively) and PFS (P = 0.010 and P < 0.001, respectively). sLeX, MCP-1 and IP-10 remained significant in multivariate survival analysis. CONCLUSION: Elevated serum sLeX was associated with invasive cancer but not DCIS. High serum sLeX levels were associated with inflammatory mediators and may play a role in facilitating local invasion of breast tumor. Furthermore, serum MCP-1, IP-10 and sLeX may have prognostic value in breast cancer.

Development of a sandwich ELISA for the 5.9-kDa fibrinogen alpha C chain fragment detected by serum proteome analysis.

PURPOSE: We previously identified novel biomarker candidates in heavy consumers of alcohol using serum proteome analysis. Among several candidates, a 5.9 kDa peptide identified as a fragment of the fibrinogen alpha C chain (FIC5.9) was the most promising. To move FIC5.9 toward potential diagnostic use, we developed an enzyme immunoassay that enables measurement of serum FIC5.9 levels. EXPERIMENTAL DESIGN: Two monoclonal antibodies specific to the N and C-termini of the 5.9-kDa peptide were used to develop a FIC5.9 sandwich ELISA. The assay was evaluated by comparing the results with those obtained by the stable isotope-labeled dilution mass spectrometry (SID-MS) using the ClinProt™ system. RESULTS: The ELISA results correlated with the SID-MS findings (slope=0.795, intercept=-0.011, r(2) =0.908) and the performance of the ELISA was satisfactory in terms of recovery (98.5-103.0%) and within-run (1.4-4.7%) and between-day (2.8-8.4%) reproducibility. The assay was capable of detecting changes in FIC5.9 during abstinence from drinking in patients with alcohol dependency (p<0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: The sandwich ELISA developed in this study will be useful for validation of the diagnostic significance of serum FIC5.9 levels in various pathological conditions, including alcoholism.

Adsorption of urinary proteins on the conventionally used urine collection tubes: possible effects on urinary proteome analysis and prevention of the adsorption by polymer coating.

One possible factor determining recovery of trace amount of protein biomarker candidates during proteome analyses could be adsorption on urine tubes. This issue, however, has not been well addressed so far. Recently, a new technical device of surface coating by poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)) (poly(MPC-co-BMA)) has been developed mainly to prevent the adsorption of plasma proteins. We assessed whether conventionally used urine tubes adsorb trace amount of urinary proteins and, if any, whether the surface coating by poly(MPC-co-BMA) can minimize the adsorption. Proteinuric urine samples were kept in poly(MPC-co-BMA)-coated and noncoated urine tubes for 15 min and possibly adsorbed proteins and/or peptides onto urine tubes were analyzed by SDS-PAGE, 2-DE, and the MALDI-TOF MS. It was found that a number of proteins and/or peptides adsorb on the conventionally used urine tubes and that surface coating by poly(MPC-co-BMA) can minimize the adsorption without any significant effects on routine urinalysis test results. Although it remains to be clarified to what extent the protein adsorption can modify the results of urinary proteome analyses, one has to consider this possible adsorption of urinary proteins when searching for trace amounts of protein biomarkers in urine.

Generation of a monoclonal antibody specific for tissue-nonspecific alkaline phosphatase and its use in a clinical diagnostic study.

Tissue-nonspecific alkaline phosphatase (TNSALP) in serum comprises liver alkaline phosphatase (liver-ALP) and bone alkaline phosphatase (bone-ALP). Liver-ALP is a marker of liver disease; thus a specific method for its measurement would be useful. Measurement of ALP by electrophoresis is difficult, although all of the isozymes can be assessed simultaneously. Total ALP can also be measured by automated analyzer, but it is difficult to determine the cause of a high ALP value because bone-, intestine-, placenta-, and tumor-ALP are measured together. Thus, anti-TNSALP monoclonal antibodies that can resolve these problems are needed. Here we have generated an anti-TNSALP monoclonal antibody, 3-29-3R. This clone has specificity to liver-ALP rather than to bone-ALP. In electrophoresis, 3-29-3R reacted with TNSALP and shifted the bands. The use of 3-29-3R enabled easy interpretation of the results. Furthermore, we tested 3-29-3R by developing an immunocapture enzymatic assay (IEA). Preliminary results of the IEA show that this method is effective for measurement of liver-ALP. Thus, the monoclonal antibody that we have established may be a useful tool for clinical diagnosis.

Development and characterization of novel monoclonal antibodies against tartrate-resistant acid phosphatase 5.

Serum band 5 tartrate-resistant acid phosphatase (TRACP 5; EC 3.1.3.2) is a glycoprotein that exists as two very similar isoforms, TRACP 5a and TRACP 5b. The similarity of these two isoforms has made it difficult to establish monoclonal antibodies specific for either isoform. We report here the development of a monoclonal antibody with high specificity for TRACP 5b. We prepared TRACP 5b antigens from four sources: TRACP 5b purified from human bone, recombinant TRACP 5 from Escherichia coli, recombinant TRACP 5 from insect cells, and a synthetic TRACP 5b peptide. Thirty-seven mice were each immunized with 1 of the 4 different TRACP antigens to generate 473 antibody-producing clones. Three of these clones, Trk27, Trk49, and Trk62, reacted with TRACP 5b. These three clones were all established from mice exposed to native bone TRACP 5b antigen. In fact, none of the other antigens were able to generate anti-TRACP 5b monoclonal antibodies in mice. Furthermore, Trk62 interacted more strongly with TRACP 5b than with TRACP 5a. These results suggested that although recombinant proteins can be effective antigens, the native TRACP 5 protein might be more effective at generating monoclonal antibodies of greater specificity due to its more faithful representation of the native three-dimensional structure of the protein.