African American esophageal squamous cell carcinoma expression profile reveals loss of detox networks

Esophageal carcinoma is the third most common gastrointestinal malignancy worldwide and is generally unresponsive to therapy. African Americans have an increased risk for esophageal squamous cell cancer (ESCC), the subtype that shows marked variation in geographic frequency. To identify key genes involved in ESC carcinogenesis in African Americans we conducted microarray expression profiling and found a significant dysregulation of genes encoding stress response and drug-metabolizing enzymes, mainly in NRF2 pathway. The involvement of NRF2 mediated oxidative damage represent a key step in the evolution of African American ESCC. Loss of activity of these enzymes would confer increased sensitivity of esophageal cells to xenobiotics, such as alcohol and tobacco smoke, and may account for the high incidence of ESCC in this ethnic group. The differential expression profile also indicates an inflammatory component and tissue regeneration in ESCC tumorigenesis. Together, these findings suggest a remarkable interplay of genetic and environmental factors in the pathogenesis of African American ESCC. Fourteen paired Human biopsy specimens collected from African Americans diagnosed with Esophageal Squamous Cell Carcinoma (ESCC). Seven of the fourteen specimens represent ESCC while the remaining represent paired healthy tissue.