We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP.

Clarithromycin is a macrolide antibiotic widely used for eradication of Helicobacter pylori infection, and thus resistance to this antibiotic is a major cause of treatment failure. Here, we present the results of a retrospective observational study of clarithromycin resistance (Cla-res) in 4744 H. pylori-infected patients from Central Hungary. We use immunohistochemistry and fluorescence in situ hybridization on fixed gastric tissue samples to determine H. pylori infection and to infer Cla-res status, respectively. We correlate this information with macrolide dispensing data for the same patients (available through a prescription database) and develop a mathematical model of the population dynamics of Cla-res H. pylori infections. Cla-res is found in 5.5% of macrolide-naive patients (primary Cla-res), with no significant sex difference. The model predicts that this primary Cla-res originates from transmission of resistant bacteria in 98.7% of cases, and derives from spontaneous mutations in the other 1.3%. We find an age-dependent preponderance of female patients among secondary (macrolide-exposed) clarithromycin-resistant infections, predominantly associated with prior use of macrolides for non-eradication purposes. Our results shed light into the sources of primary resistant cases, and indicate that the growth rate of Cla-res prevalence would likely decrease if macrolides were no longer used for purposes other than H. pylori eradication.

The hepatocyte growth factor/scatter factor (HGF/SF) tyrosine kinase (TK) receptor c-Met plays a crucial role in the development of the invasive phenotype of tumors and thus represents an attractive candidate for targeted therapies in a variety of malignancies, including human malignant melanoma (MM). In contrast to what has been shown previously, we were not able to detect any genetic alterations, either in the juxtamembrane- or in the TK-domain of c-Met, in the studied MM cell lines. Nevertheless, c-Met was constitutively active in these cell lines without exogenous HGF/SF stimulation. The active receptor was localized to the adhesion sites of the cells. Addition of the c-Met TK inhibitor SU11274 specifically decreased the phosphotyrosine signal at the focal adhesions sites, which was accompanied by a decrease in cell proliferation as well as an increase in apoptotic cells. In addition, non-apoptotic concentrations of SU11274 significantly reduced the in vitro migratory capacity of MM cells in the modified Boyden-chamber assay. Administration of SU11274 significantly decreased primary tumor growth as well as the capacity for liver colony formation of MM cells in SCID mice. Our study provides the first evidence for an in vivo antitumor activity of SU11274 in a human melanoma xenograft model, and suggests c-Met as a valid target for the therapy of MM. Consequently, SU11274 treatment might represent a useful strategy for controlling melanoma progression and metastasis in patients with MM.

Oncogenic activation of the epidermal growth factor receptor (EGFR) signaling pathway occurs in a variety of tumor types, albeit in human melanoma, the contribution of EGFR is still unclear. The potential role of EGFR was analyzed in four BRAF-mutant, one NRAS-mutant and one wild-type NRAS-BRAF-carrying human melanoma cell lines. We have tested clinically available reversible tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib, irreversible EGFR-TKI pelitinib and a reversible experimental compound PD153035 on in-vitro proliferation, apoptosis, migration as well as in-vivo metastatic colonization in a spleen-liver model. The presence of the intracellular domain of EGFR protein and its constitutive activity were demonstrated in all cell lines. Efficacies of EGFR-TKIs showed significant differences, and irreversible inhibition had the strongest antitumor potential. Compared with BRAF-mutant cells, wild-type BRAF was associated with relative resistance against gefitinib. In combination with gefitinib, selective mutant BRAF-inhibitor vemurafenib showed additive effect in all BRAF-mutant cell lines. Treatment of BRAF-mutant cells with gefitinib or pelitinib attenuated in-vitro cell migration and in-vivo colonization. Our preclinical data suggest that EGFR is a potential target in the therapy of BRAF-mutant malignant melanoma; however, more benefits could be expected from irreversible EGFR-TKIs and combined treatment settings.

Invasive micropapillary carcinoma of the breast (IMPC) has been in the focus of several studies given its specific histology and clinicopathological course. We analysed mRNA expression profiles and the prognostic value of 43 genes involved in cell polarity, cell-adhesion and epithelial–mesenchymal transition (EMT) in IMPC tumors and compared them to invasive breast carcinomas of no special type (IBC-NST). IMPCs (36 cases), IBC-NSTs (36 cases) and mixed IMPC-IBC NSTs (8 cases) were investigated. mRNA expression level of selected genes were analysed using the NanoString nCounter Analysis System. Distant metastases free survival (DMFS) intervals were determined. Statistical analysis was performed using Statistica 13.5 software. Twelve genes showed significantly different expression in the IMPC group. There was no difference in DMFS according to histological type (IBC-NST vs. IMPC). High CLDN3, PALS1 and low PAR6 expression levels in the entire cohort were associated with shorter DMFS, and PALS1 was proven to be grade independent prognostic factor. Positive lymph node status was associated with higher levels of AKT1 expression. Differences in gene expression in IMPC versus IBC-NST may contribute to the unique histological appearance of IMPCs. No marked differences were observed in DMFS of the two groups. Altered gene expression in the mTOR signaling pathway in both tumor subtypes highlights the potential benefit from AKT/mTOR inhibitors in IMPCs similarly to IBC-NSTs.