Background and Objective: Several reports indicate the effect of obesity on the rise of breast cancer prevalence in different societies. Several laboratory methods have been applied in order to understand molecular mechanisms and biochemical markers associated with breast cancer, many of which are still unknown. In this study, we investigate the relation between protein profile of breast tumor tissue and body mass index (BMI) in women with invasive ductal breast cancer.

Materials and Methods: In this descriptive analytical study, 10 patients diagnosed with invasive ductal breast cancer were chosen and divided into two groups based on their BMI, higher mean (33.41) and lower mean (26.04). Homogenized tumor proteins were analyzed with proteomics system. In this method, two-dimensional electrophoresis and MALDI-TOF MS / MS were used. Statistical analysis was done by t-test and Image master 2D platinum 6.0.

Results: In this study, glyceraldehyde 3-phosphate dehydrogenase expression increased significantly in the biopsy of the higher mean BMI group in comparison with the lower mean BMI=26.04 group (P <0.05). In contrast, the expression of cytokeratin 19 in the higher mean BMI group compared to the other group showed a significant reduction (P <0.05). Furthermore Apo A-1 expressed only in the biopsy of the lower mean BMI group and HSP27 expressed only in the higher mean BMI group.

Conclusion: The findings of this study indicate some differences in protein spectrum between the biopsies of lower and higher mean BMI groups of breast cancer patients. Furthermore the four proteins mentioned in the results probably influence molecular mechanisms linking obesity to breast cancer, but more studies are needed.