ABSTRACT
Helicobacter pylori [H. pylori] is the main cause of several gastro-duodenal diseases, and is also related to a variety of extragastric diseases, including liver diseases. It was classified as class I carcinogen. Several risk factors for the development of hepatocellular carcinoma [HCC] are identified. Continuing attempts are being made to identify other risk factors. The objective of this study was to evaluate the presence of H. pylori DNA in human HCC to determine if H. pylori may contribute to the development of this disease. Liver specimens from 33 patients with HCC as well as from 6 patients who did not have malignancy; 4 had cholelithiasis and 2 had hepatic hemangioma considered as control, were studied. Liver samples were examined by polymerase chain reaction [PCR] for the presence of genomic 16S rRNA of Helicobacter genus using specific primers. Besides, other genes; 26 kDa cell surface protein, cag A, and vac A, specific for H. pylori and mdh specific for E. coli were also screened by PCR. In addition, the specimens were examined for H. pylori by immunohistochemical procedure using anti-H. pylori antibody. Helicobacter genus-specific 16S rRNA was found in 12 out of the 33 [36.4%] samples of HCC tissues, whereas none of the 6 control liver specimens were found to harbor this rRNA. The H. pylori species-specific 26 kDa protein gene was detected in 11 of the 12 [91.7%] samples positive for the Helicobacter 16S rRNA gene thus confirming the presence of H. pylori DNA in 33.3% of the HCC samples. Within these 11 HCC samples, the cag A gene was detected in only 3, whereas the vac A and mdh genes were not detected. Helicobacter pylori immunostaining was recognized in 7 HCC specimens [21.2%], which were also positive for H. pylori species-specific DNA detection by PCR with statistically very high significant association [p = 0.0001]. The presence of microscopic evidence of hepatitis [10 cases] and cirrhosis [15 cases] presented a significant association with both H. pylori DNA detection [p = 0.0320 and 0.0260 respectively] and immunoreactivity [p = 0.0075 and 0.0158 respectively]. These data indicate that the detection of H. pylori by means of molecular methods and immunohistochemistry in human HCC tissue supports the concept of the possible association between H. pylori and HCC development. However, their eventual role in hepatocarcinogenesis, although it is plausible, remains to be proven