New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...

90 CHAPTER 4. (BIO-)MEDICAL APPLICATIONS
4.4 Identification of Proteomic Fingerprints in Blood
Serum by High-sensitive Bioinformatic Analysis
of SELDI-TOF MS Data for Detection of
Testicular Germ Cell Cancer
This study was performed in close collaboration with Dr. Romy Strenziok from
the Charité Berlin.
Testicular germ cell cancer is the most common solid malignant tumor
in young men. (Huyghe, Plante and Thonneau, 2007) showed that the incidence
of testicular tumors has shown a steady increase in Europe over the past
decades. Although numerous molecular parameters have been established as
diagnostic and prognostic tools for a variety of tumor entities, testicular germ
cell cancer and its molecular patterns are not well understood, and the literature
addressing this important issue is sparse.
Routine clinical testing with serum markers is of high diagnostic value
and should therefore be included in the clinical workup of testicular masses.
However, these markers are only considered useful for follow-up checks and
cannot adequately replace other diagnostic procedures like testicular palpation,
ultrasound, and surgical exploration of suspicious testicular masses. The
only available tumor marker for testicular seminoma, beta-human chorionic
gonadotropin (beta-HCG), is elevated in approximately 18 % of the cases
(Schmid et al., 1999). Thus there is clearly a need for new molecular markers.
In this study we use the ProteinChip�system based on surface-enhanced
laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS)
(see section 3.2) to identify biomarkers by analyzing aberrant protein patterns
in complex biological mixtures. This technology has already been beneficially
applied in urological diseases such as renal cell cancer (Tolson et al., 2004)
and prostate cancer (Qu et al., 2002) and for urinary protein identification in
transitional cell carcinoma of the bladder (Mueller et al., 2005; Vlahou et al.,
2001; Liu et al., 2005).
The aim of this study is to examine serum samples of seminoma patients by
SELDI-TOF MS and assess the predictive value of this technique at primary
tumor manifestation in different clinical stages.
4.4.1 Study Material
All clinical samples and data were obtained from the Charité-Universitätsmedizin
Berlin, Urologische Klinik und Hochschulambulanz, Campus Benjamin Franklin,
Berlin and from the Vivantes Klinikum Am Urban, Klinik für Urologie, Berlin.
Serum procurement was done with the ethical approval by the Institutional
Review Board.
Blood was drawn into standard serum collection tubes and allowed to clot
at 4� for 1 hour, warmed to room temperature and centrifuged for 10 minutes
at 2500g. After centrifugation, all serum samples were immediately prepared
and snap-frozen in liquid nitrogen before storage at -80�. The clinically
diagnosed testicular germ cell cancers were confirmed by histopathological
expertising following inguinal orchiectomy. Seminoma components were immunohistologically
verified by tumor-associated antigen profiling with cluster