TGFB1 and hepatitis C virus infection: The search used a combination of MeSH terms such as "Transforming Growth Factor beta 1," "Polymorphism, Genetic," "Cirrhosis," "Hepatitis C," and "Liver Diseases." Keywords such as "TGF-beta 1," "polymorphism," "cirrhosis," "hepatitis C," "liver disease," and "genetic variations" were also included.