Genotyping of the cagA gene of Helicobacter pylori on immunohistochemistry with East Asian CagA-specific antibody

• Published in: Pathology international Vol. 58; no. 4; pp. 218 - 225
• Main Authors: Kanada, Ryoko, Uchida, Tomohisa, Tsukamoto, Yoshiyuki, Nguyen, Lam Tung, Hijiya, Naoki, Matsuura, Keiko, Kodama, Masaaki, Okimoto, Tadayoshi, Murakami, Kazunari, Fujioka, Toshio, Yanagisawa, Shigetaka, Moriyama, Masatsugu
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Blackwell Publishing Asia 01.04.2008
• Subjects: Amino Acid Motifs - genetics; Amino Acid Sequence; Antibody Specificity; Antigens, Bacterial - chemistry; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Biomarkers - metabolism; CagA; EPIYA motif; Gastric Mucosa - metabolism; Gastric Mucosa - microbiology; Gastric Mucosa - pathology; Genes, Bacterial; Genotype; Helicobacter Infections - diagnosis; Helicobacter Infections - metabolism; Helicobacter Infections - microbiology; Helicobacter pylori; Helicobacter pylori - genetics; Helicobacter pylori - immunology; Helicobacter pylori - isolation & purification; Humans; Immunohistochemistry; Molecular Sequence Data; Polymorphism, Genetic; Sequence Analysis, DNA
• ISSN: 1320-5463; 1440-1827
• DOI: 10.1111/j.1440-1827.2008.02214.x

The cytotoxin‐associated antigen A (CagA) of Helicobacter pylori prevalent in East Asian countries, where the mortality rate due to gastric cancer is high, has been reported to be structurally different from that in Western countries, where the gastric cancer mortality rate is relatively low. Based on the structural features of the EPIYA motifs located at the carboxyl terminal of the protein, CagA was subdivided into two types: East Asian CagA and Western CagA. A recent study suggested that immunohistochemistry with anti‐East Asian‐specific antibody (α‐EAS Ab), which was specifically immunoreactive with East Asian CagA but not with Western CagA, may be useful for diagnosis of the cagA genotype. To further evaluate the value of this diagnostic method in terms of sensitivity, specificity, and accuracy, 143 gastric biopsy specimens with α‐EAS Ab were analyzed on immunohistochemistry and compared with the sequencing of the cagA gene. It was found that diagnosis of the cagA genotype of H. pylori on immunohistochemistry using the α‐EAS Ab was highly sensitive (sensitivity 93.2%) and specific (specificity 72.7%), suggesting that immunohistochemical diagnosis of the cagA genotype is useful for diagnosis of the cagA genotype.