Proteomic analysis of archival breast cancer serum.

Large cohorts of archival samples are stored in tissue banks worldwide yet their contribution to biomarker discovery is limited. Proteomic profiling technologies have potential for early screening and diagnosis of cancer, and data from such samples can be the answer for many clinical questions. Here we introduce the notion of archival samples proteomics. Using SELDI-TOF MS analysis, we compared 30-year-old archival serum samples of healthy volunteers and patients diagnosed with non metastatic breast cancer. To validate the reproducibility of our results, analysis of the same samples was repeated in a different centre under standardised settings. Plausible differentially expressed protein peaks between the breast cancer and control groups were repeatedly detected. Our pilot study showed highly reproducible and concordant results between two independent analyses conducted in different centres. The feasibility and reliability of profiling serum archives of women with breast cancer was tested in this pilot study. Our results imply that proteomic profiling of serum may have an important role in biomarkers discovery regardless of the storage period. Clearly, multicentre validation of larger archival cohorts is vital.