Candidate biomarkers in renal cell carcinoma

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Background: Renal cell carcinoma (RCC) represents a heterogeneous disease with widely varying prognosis. Therefore, the screening for biomarkers, which allow the diagnosis as well as the assessment of the individual risk of disease progression and mortality are a prerequisite for the selection of patients for different modes of therapies and the implementation of individually tailored surveillance protocols.

Methods: Various proteome-based technologies such as 2DE-based proteomics, PROTEOMEX or ligandomics in combination with mass spectrometry have been applied. Bioinformatic data mining led to the categorization and priorization of the respective target lists. Selected candidate targets were further independently verified by qRT-PCR, Western blot and/or immunohistochemistry.

Results: A large series of differentially expressed/immunoreactive proteins have been identified in clear cell RCC when compared to normal kidney epithelium. With the different approaches distinct sets of potential candidate targets were defined and categorized into different protein families and functions and according to their cellular localization. Moreover, the limited sharing rates between the respective target lists demonstrate their complementarity. Some selected markers were further validated by qRT-PCR, Western blot analysis and/or immunohistochemical stainings of tissue micro arrays comprised of RCC lesions of different TNM classification and histology revealing distinct expression pattern in regard to the RCC subtype, tumor grading,staging or additional molecular features. Using the ligandomics approach proteins have been identified, which were able to mount an immune response in vitro.

Conclusions: Some candidate markers might have the potential to be used as diagnostic and prognostic factors if not as novel targets for therapy and thus could be employed for the expression profiling of a larger series of RCC patients.

No significant financial relationships to disclose.

Clinical correlation of antimitochondrial antibodies

BACKGROUND

Antimitochondrial antibodies (AMA) are a hallmark of primary biliary cirrhosis (PBC). They are believed to be absolutely disease specific. It does occur that patients with positive AMA are diagnosed with PBC in the absence of liver specific signs and symptoms. The aim of the present study was to examine the disease spectrum of unselected AMA positive patients of an university hospital.

METHODS

All of the AMA tests performed in the immunological laboratory of the hospital between 1992 and 1998 were examined for positivity. 100 patients with a positive result were analyzed retrospectively for diagnosis, clinical and laboratory features.

RESULTS

61 patients suffered from liver diseases and 39 from non-liver diseases. The patients with liver diseases were 36 patients with PBC, 2 patients with PBC/PSC-overlap syndrome, 4 patients with autoimmune hepatitis and 19 patients with different liver diseases of other than autoimmune origin. The 39 patients with non-liver diseases included 9 patients with systemic autoimmune diseases, 3 patients with organ-specific autoimmune diseases, 8 patients with carcinoma and 19 patients with different diseases. 97 patients had an ELISA test for antibodies to the mitochondrial antigen M2 performed in addition to the immunofluorescence test for AMA. 73 patients had positive values for anti-M2 antibodies and 24 patients had negative results. Anti-M2 antibody values were divided in negative, low (5-100 U/ml), medium (101-1000 U/ml), high (1001-10000 U/ml) and very high (>10000 U/ml). Very high and high anti-M2 values were present mainly in patients with PBC and some patients with other liver diseases, medium high and low values in patients with different disease groups. In this unselected patient population only one third of AMA positive patients had an established diagnosis of PBC, about 10% a diagnosis of a systemic autoimmune disease and 3 % had other organ-specific autoimmune diseases. It can be concluded that, although high titers of antibodies against M2 are present mainly in patients with PBC, medium high and low titers may be present in patients lacking symptoms of PBC.

CONCLUSIONS

Although there is the possibility that the patients will develop the disease in the future, the presence of AMA alone does not seem to be sufficient to establish a diagnosis of PBC in a patient population in which at a given time point only 38 % of AMA positive patients have the disease.

On haemodilution therapy for patients with sudden loss of hearing: clinical and rheological results

In cases of sudden loss of hearing, it must be assumed that a microcirculatory disturbance is involved, on the basis of a vasospasm of the afferent blood vessels and a "sludging phenomenon" in the region of the distal end-arteries of the cochlea. The microcirculatory disturbance results in an impairment of the O2 concentration in the perilymph, which can bring about disturbances, which are usually of short duration, and reversible changes in metabolism and structure of the hair cells. For this reason the therapeutic objective should be a reduction in the blood viscosity and flow resistance, plus a reduction in surface tension and an influence on the glycogenolytic metabolism of the erythrocytes. The therapeutic concept here is to be sought in a hypervolaemic haemodilution therapy with plasma substitutes. Care should be taken in the selection of the plasma substitute that not only parameters crucial to the macrocirculation are influenced, such as PCV and whole blood viscosity, but also those significant for the microcirculation, such as plasma viscosity and erythrocyte aggregation. A rheologically effective plasma expander would appear to have been found in the 10% hydroxyethyl starch 200/0.5, which together with naftidrofuryl would appear to be a proven agent in the combination therapy for sudden loss of hearing, due to its positive effect on plasma viscosity and erythrocyte aggregation, as shown by the significantly better mean increase in hearing on completion of therapy.