Ovarian serous
carcinomas (OSCs) comprise over half of all ovarian
carcinomas and account for the majority of
ovarian cancer-related deaths. We used a 2-dimensional liquid-based
protein mapping strategy to characterize global
protein expression patterns in 19 OSC
tumor samples from 15 different patients to facilitate molecular classification of
tumor stage.
Protein expression profiles were produced, using pI-based separation in the first dimension and hydrophobicity-based separation in the second dimension, over a pH range of 4.0-7.0. Hierarchical clustering was applied to
protein maps to indicate the
tumor interrelationships. The 19
tumor samples could be classified into two different groups, one group associated with low stage (Stage 1)
tumors and the other group associated with high stage (Stages 3/4)
tumors.
Proteins that were differentially expressed in different groups were selected for identification by LTQ-ESI-MS/MS. Fourteen of the selected
proteins were overexpressed in the low stage
tumors; 46 of the
proteins were overexpressed in the high stage
tumors. These
proteins are known to play an important role in cellular functions such as glycolysis, protein biosynthesis, and cytoskeleton rearrangement and may serve as markers associated with different stages of OSCs. To further confirm the stage-dependent
protein identifications,
Lamin A/C and
Vimentin expression in ovarian serous
carcinomas was assessed by immunohistochemistry using ovarian
tumor tissue microarrays for 66 samples.