Introduction: The molecular mechanisms involved in the development and progression of breast cancer have yet to be determined. In the present study, the proteome of cancerous beast and adjacent normal tissues were compared.
 
Materials & Methods: In a cohort study, the cancer tissues and adjacent normal tissues were obtained from 5 female patients with ductal carcinoma in stage 3. The total protein contents of cancer and adjacent normal tissues were extracted. The protein expression levels were examined by Image Master 2D Platinum software following two-dimensional gel electrophoresis. MALDI-TOF MS/MS mass spectrometry was used for proteins identification.
 
Findings: The constant region of Ig gamma-1 chain and beta subunit of hemoglobin were exclusively detected in the cancer and adjacent normal tissues, respectively. The expression of serum albumin and collagen VI alpha chain in the cancer tissue was significantly lower than the normal tissue (P <0.05). In contrast, the expression of a single peptide matching to cytoskeletal type I and II keratin significantly increased in the cancer tissue compared to the normal tissues (P <0.05).
 
Discussion & Conclusion: As the output of our investigation, it seems that proteome of cancerous tissue is extensively different from the adjacent one. Therefore, proteomic approach might be a promising tool for monitoring  breast tumorigenesis. However, this needs to be confirmed in future.