The ubiquitin system may be involved in HCV-related hepatocarcinogenesis and in the development of other cancers.

My thanks and praise go first of all to God who created us, taught us what we did not know, and showed us the right path to live, think, and thank him. No words can praise him the way he deserves. I am extremely grateful to Dr Tim Harrison whose guidance and support were essential throughout all steps of this study. His valuable comments and critical reading helped me editing this thesis. Thanks are also to Dr Vincent Emery for his encouragement and support. I would like to acknowledge the generous help, advice and friendship of Dr Roger Ling who saw me through the whole study. His help is gratefully appreciated.

My thanks and praise go first of all to God who created us, taught us what we did not know, and showed us the right path to live, think, and thank him. No words can praise him the way he deserves. I am extremely grateful to Dr Tim Harrison whose guidance and support were essential throughout all steps of this study. His valuable comments and critical reading helped me editing this thesis. Thanks are also to Dr Vincent Emery for his encouragement and support. I would like to acknowledge the generous help, advice and friendship of Dr Roger Ling who saw me through the whole study. His help is gratefully appreciated.