Jens Werner

Objectives Comprehensive assessment of cMET and HER family receptor tyrosine kinases expression, changes of expression during metastatic progression, amplification status of the MET gene, and correlations with patient characteristics in pancreatic ductal adenocarcinoma (PDAC) was conducted. Methods We investigated 56 PDACs and corresponding lymph node metastases for HER1 to HER4 and cMET expression by immunohistochemistry, as well as cMET gene copy numbers by chromogenic in situ hybridization. Results Of all receptor tyrosine kinases evaluated, cMET expression was highest with 46.5% of tumors showing moderate or strong expression and a weak correlation with gene copy number status (P = 0.04; Spearman ρ = 0.28). cMET expression was increased in metastases. In contrast, expression levels of HER family receptors were generally low both in primaries and metastases. A weak yet significant correlation of HER1 and cMET expression levels was observed (P < 0.001; Spearman ρ = 0.44) and HER1 was often present in poorly differentiated tumors (G3, P = 0.049). Conclusions Our data suggest that cMET might constitute an interesting molecule for combining targeted and chemotherapeutic approaches in PDAC, because expression is frequent and increased during metastatic progression. In PDAC, cMET protein expression might be a more useful stratification biomarker than cMET gene amplification, which does not seem to be its primary regulator.

To evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance. After Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed. Mean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm³, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm³, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone. There is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

Prognosis of patients with carcinoma of the exocrine pancreas is particularly poor. A combination of chemotherapy with immunotherapy could be an option for treatment of pancreatic cancer. The aim of this study was to perform an immunomonitoring of 17 patients with pancreatic cancer from the CapRI-2 study, and tumor-bearing mice treated with combination of chemo (radio) therapies with interferon-2α. Low doses of interferon-2α led to a decrease in total leukocyte and an increase in monocyte counts. Furthermore, we observed a positive effect of interferon-2α therapy on the dendritic cells and NK (natural killer) cell activation immediately after the first injection. In addition, we recorded an increased amount of interferon-γ and IL-10 in the serum following the interferon-2α therapy. These data clearly demonstrate that pancreatic carcinoma patients also show an immunomodulatory response to interferon-2α therapy. Analysis of immunosuppressive cells in the Panc02 orthotopic mouse model of pancreatic cancer revealed an accumulation of the myeloid-derived suppressor cells in spleens and tumors of the mice treated with interferon-2α and 5-fluorouracil. The direct effect of the drugs on myeloid-derived suppressor cells was also registered in vitro. These data expose the importance of immunosuppressive mechanisms induced by combined chemo-immunotherapy.