In common with other tumor types, ovarian cancer is a genetic disease and work at the DNA or RNA level is crucial to gain an understanding of the genetic changes leading to tumor formation. Phenotypic change, however, is the result of loss or aberrant expression of normal protein or expression of a mutated form. Proteins are the front end of biology and for this reason, analysis of protein expression is of paramount importance. Any researcher detecting changes in DNA or RNA without corresponding changes in protein levels or turnover should question whether the changes are artefactual or coincidental. Often researchers are put off measuring proteins because of the relative complexity and perceived lack of sensitivity that protein detection systems exhibit. When it is possible to design reverse transcription polymerase chain reaction (RT-PCR) and PCR reactions capable of detecting and quantifying single mRNA/DNA copies, then it is often easier to demonstrate mRNA expression rather than investigating proteins.