The effect of Trastuzumab treatment on B-cell kinase activities assessed by microarray derived phosphorylation profiles.

Cancer is associated with activation and deactivation of a wide range of
proteins. With the development of the peptide microarray system by Pamgene, it
is possible to measure the phosphorylation of a wide variety of peptide
substrates, and thus kinase enzyme activities, at once. Using a phosphopeptide
capture assay, the SELDI-TOF MS technology can also be applied in generating a
protein phosphorylation profile. These protein phosphorylation profiles can
tell us more about the signalling pathways involved in cancer progression.

Objectives to explore: :
1-whether kinase activities can be detected in lymphocytes derived from cancer
patients, using a peptide array or a phosphopeptide capture SELDI-TOF MS assay.
2-how many cells are needed for the generation of a kinase activity profile by
a peptide array and SELDI-TOF MS assay.
3-whether an (indirect) effect of patient treatment with trastuzumab, targeting
Her2/Neu/ErbB2 (receptor tyrosine kinase), is detectable by changes in the
phosphorylation profile from lysates of lymphocytes sampled before and after
patient treatment, using a peptide array or using a phosphopeptide capture
SELDI-TOF MS assay.
4-Whether changes in kinase profile can be correlated with the exposure to
trastuzumab in plasma.
5-Whether changes in the SELDI-TOF MS protein profiles of PMBC lysates and
serum are correlated with patient exposure to trastuzumab.
6-Whether changes in the kinase profile are correlated with changes in the
SELDI-TOF MS protein profiles of PBMC lysates or serum.
7-Whether changes in kinase activity are correlated with metabolic changes in
urine.

In total, thirty (30) patients will be included. Fifteen (15) patients who will
be treated with trastuzumab will be asked to donate blood and urine samples at
predefined timepoints during the first 4 cycles of treatment in order to
determine kinase activities in white blood cells and to quantitate trastuzumab
levels in serum and determine metabolites in urine. Fifteen patients whose
treatment is discontinued will be asked to donate blood samples at predefined
timepoints over a period of 8 weeks in order to construct a elimination curve
of trastuzumab. These patients must have completed at least 4 months of
trastuzumab treatment.

Local hospital procedures for dosage and administration of trastuzumab will be
followed. Dose modifications because of developed toxicities are left to the
discretion of the responsible oncologist. Discontinuation of treatment is left
to the discretion of the responsible oncologist.

The study procedures in this study include the collection of blood as well as
of urine samples. Participants of this study might get a bruise due to drawing
of blood samples.