HCV infection becomes a major health problem. So there is a need for improvements in diagnosis, prognosis and treatment of the disease. In this book, we concerned with studying biomarkers that can be used to help in detection of the progression of disease and prediction of the response to IFN-therapy. The book included a study on the relationship between the LMP 7 gene polymorphism and response to IFN-therapy in the Egyptian HCV infected patients. The study found a great association between the response to IFN-therapy in HCV infected patients and LMP 7 gene. so, the LMP 7 gene can be used as a biomarker for prediction of response to IFN-therapy.