Toward Broader Inclusion of Liquid Chromatography-Mass Spectrometry in the Clinical Laboratory

Oncopeptidomics--a commentary on opportunities and limitations

Cancer cells exhibit specific changes in protein expression and alterations in proteolytic activities. Peptides are capable of reflecting these pathological changes and are educible by dedicated analytical technologies. Oncopeptidomics can be defined as the comprehensive multiplexed analysis of endogenous peptides from a biological sample, under defined conditions, to discover probable valid peptide tumor biomarker. Here, mass spectrometry has shown its potential as a comprehensive peptide profiling tool. The efforts to arrive at diagnostically relevant biomarkers may have been underestimated. The establishment of novel cancer biomarkers will necessitate a multidisciplinary effort and presumably require a duration comparable to the drug development process. This review will address current concepts, new perspectives and the developmental process leading to clinically useful peptide tumor markers.

Clinical Outcomes of Renal Transplantation Using Liquid Chromatographic Monitoring of Tacrolimus

It is suggested that specific methods of Tacrolimus monitoring rather than immunoassays which over-estimate Tacrolimus levels, should be used in transplant recipients. There is limited data, however, comparing clinical outcomes of renal transplantation using each of these techniques. In this study, 40 renal transplant recipients with Tacrolimus monitoring by Microparticle Enzyme Immunoassay (MEIA; target trough level 10-15 ng/ml) were compared with 40 patients monitored by High Performance Liquid Chromatography with Tandem Mass Spectrometry (HPLC-MS; target trough level 8-13 ng/ml). All received anti CD25 antibody induction and Mycophenolate Mofetil in a steroid sparing protocol. No demographic differences were seen between MEIA and HPLC-MS groups. All patients were followed for 6 months. Patient survival was 100% in both groups; graft survival was 100% in the MEIA group and 97.5% in the HPLC-MS group. The groups did not differ in the number of dose changes required in the first 6 months or in the number of patients displaying Tacrolimus levels within target range at three and six months. Delayed graft function occurred in 14 patients in the MEIA group and 12 patients in the HPLC-MS group (P = NS). Biopsy-proven acute rejection occurred in 4 patients in the MEIA group and 1 patient in the HPLC-MS group (P = 0.17). Biopsy proven acute Tacrolimus nephrotoxicity occurred in 6 patients in the MEIA group, and 7 in the HPLC-MS group (P = NS). No difference was seen in serum creatinine or estimated creatinine clearance at 3 or 6 months. No difference between groups was seen in systolic or diastolic blood pressure, or total cholesterol at 3 or 6 months. 2 patients in the MEIA group developed CMV disease and 1 developed posttransplantation diabetes mellitus. CMV and posttransplantation diabetes were not seen in the HPLC-MS group. 2 patients in each group developed reversible tremor. This study suggests that renal transplantation with HPLC-MS monitoring of Tacrolimus is safe and effective.