Comparative Clinical and Transcriptomal Profiles of Breast Cancer Between French and South Mediterranean Patients Show Minor but Significative Biological Differences

Background: InWestern countries, breast cancer incidence and mortality are higher than in Mediterranean countries. These differences have been ascribed to environmental factors but also to late-stage diagnostic and biological specific characteristics. Patients and Methods: Between September 2002 and September 2005, we collected clinical data by phone counselling 180 French and Mediterranean breast cancer patients and performed microarray experiments. Results: Characteristics of breast cancer in patients from Lebanon,Tunisia and Morocco were more aggressive (more SBR grade III and positive node invasion) and patients were 10 years younger at diagnos is . Sixteen differentially expressed genes such as MMP9,VEGF, PHB1, BRCA1, TFAP2C, GJA1 and TFF1 were also found. Additionally, an up-regulation of cytokeratins KRT8 and KRT18 may indicate a luminal B subtype in "South" (Lebanon, Tunisia and Morocco) tumors while "North" (France) tumors may more frequently be luminal A type. Conclusion: This study allowed the identification of specific clinical and transcriptomic parameters in patients from South Mediterranean countries.