Background: Gastroesophageal reflux disease (GERD) is associated with impaired epithelial barrier function that is regulated by cell-cell contacts. The aim of the study was to investigate the expression pattern of selected components involved in the formation of tight junctions in relation to GERD. Methods: Eighty-four patients with GERD-related symptoms with endoscopic signs (erosive: n = 47) or without them (non-erosive: n = 37) as well as 26 patients lacking GERD-specific symptoms as controls were included. Endoscopic and histological characterization of esophagitis was performed according to the Los Angeles and adapted Ismeil-Beigi criteria, respectively. Mucosal biopsies from distal esophagus were taken for analysis by histopathology, immunohistochemistry and quantitative reverse-transcription polymerase chain reaction (RT-PCR) of five genes encoding tight junction components [Occludin, Claudin-1, -2, Zona occludens (ZO-1, -2)]. Results: Histopathology confirmed GERD-specific alterations as dilated intercellular spaces in the esophageal mucosa of patients with GERD compared to controls (P < 0.05). Claudin-1 and −2 were 2- to 6-fold upregulation on transcript (P < 0.01) and in part on protein level (P < 0.015) in GERD, while subgroup analysis of revealed this upregulation for ERD only. In both erosive and non-erosive reflux disease, expression levels of Occludin and ZO-1,-2 were not significantly affected. Notably, the induced expression of both claudins did not correlate with histopathological parameters (basal cell hyperplasia, dilated intercellular spaces) in patients with GERD. Conclusions: Taken together, the missing correlation between the expression of tight junction-related components and histomorphological GERD-specific alterations does not support a major role of the five proteins studied in the pathogenesis of GERD.

The product of CDKN2A, p16 is an essential regulator of the cell cycle controlling the entry into the S-phase. Herein, we evaluated CDKN2A promoter methylation and p16 protein expression for the differentiation of hepatocellular carcinoma (HCC) from other liver tumors. Tumor and corresponding non-tumor liver tissue samples were obtained from 85 patients with liver tumors. CDKN2A promoter methylation was studied using MethyLight technique and methylation-specific PCR (MSP). In the MethyLight analysis, samples with ≥ 4% of PMR (percentage of methylated reference) were regarded as hypermethylated. p16 expression was evaluated by immunohistochemistry in tissue sections (n = 148) obtained from 81 patients using an immunoreactivity score (IRS) ranging from 0 (no expression) to 6 (strong expression). Hypermethylation of the CDKN2A promoter was found in 23 HCCs (69.7%; mean PMR = 42.34 ± 27.8%), six (20.7%; mean PMR = 31.85 ± 18%) liver metastases and in the extralesional tissue of only one patient. Using MSP, 32% of the non-tumor (n = 85), 70% of the HCCs, 40% of the CCCs and 24% of the liver metastases were hypermethylated. Correspondingly, nuclear p16 expression was found immunohistochemically in five (10.9%, mean IRS = 0.5) HCCs, 23 (92%; mean IRS = 4.9) metastases and only occasionally in hepatocytes of non-lesional liver tissues (mean IRS = 1.2). The difference of CDKN2A-methylation and p16 protein expression between HCCs and liver metastases was statistically significant (p < 0.01, respectively). Promoter methylation of CDKN2A gene and lack of p16 expression characterize patients with HCC.

The previously reported prevalence of gastric heterotopia in the cervical esophagus, also termed inlet patch (IP), varies substantially, ranging from 0.18 to 14%. Regarding cases with adenocarcinoma within IP, some experts recommend to routinely obtain biopsies from IP for histopathology. Another concern is the reported relation to Barrett’s esophagus. The objectives of the study were to prospectively determine the prevalence of IP and of preneoplasia within IP, and to investigate the association between IP and Barrett’s esophagus. 372 consecutive patients undergoing esophagogastroduodenoscopy were carefully searched for the presence of IP. Biopsies for histopathology were targeted to the IP, columnar metaplasia of the lower esophagus, gastric corpus and antrum. Different definitions of Barrett’s esophagus were tested for an association with IP. At least one IP was endoscopically identified in 53 patients (14.5%). Histopathology, performed in 46 patients, confirmed columnar epithelium in 87% of cases, which essentially presented corpus and/or cardia-type mucosa. Intestinal metaplasia was detected in two cases, but no neoplasia. A previously reported association of IP with Barrett’s esophagus was weak, statistically significant only when short segments of cardia-type mucosa of the lower esophagus were included in the definition of Barrett’s esophagus. The prevalence of IP seems to be underestimated, but preneoplasia within IP is rare, which does not support the recommendation to regularly obtain biopsies for histopathology. Biopsies should be targeted to any irregularities within the heterotopic mucosa. The correlation of IP with Barrett’s esophagus hints to a partly common pathogenesis.