title: Clinical significance of hepatitis B surface antigen mutants.
abstract: Hepatitis B virus (HBV) infection is a major public health problem in many countries, with nearly 300 million people worldwide carrying HBV chronic infection and over 1 million deaths per year due to cirrhosis and liver cancer. Several hepatitis B surface antigen (HBsAg) mutations have been described, most frequently due to a single amino acid substitution and seldom to a nucleotide deletion. The majority of mutations are located in the S region, but they have also been found in the pre-S1 and pre-S2 regions. Single amino acid substitutions in the major hydrophilic region of HBsAg, called the "a" determinant, have been associated with immune escape and the consequent failure of HBV vaccination and HBsAg detection, whereas deletions in the pre-S1 or pre-S2 regions have been associated with the development of hepatocellular carcinoma. This review article will focus on the HBsAg mutants and their biological and clinical implications.
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Coppola
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Onorato
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Minichini
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Caprio
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Starace
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Sagnelli
authors.affiliation: Nicola Coppola, Lorenzo Onorato, Carmine Minichini, Giovanni Di Caprio, Mario Starace, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, 80131 Naples, Italy.
authors.forename: Evangelista
authors.initials: E
authors.lastname: Sagnelli
keywords: Hepatitis B surface antigen mutants; Hepatitis B virus infection; Immune escape hepatocellular carcinoma; Vaccine escape