MiR-21 up-regulation in ampullary adenocarcinoma and its pre-invasive lesions.

Poor information is available on the molecular landscape characterizing the carcinogenetic process leading to ampullary carcinoma. MiR-21 is one of the most frequently up-regulated miRNAs in pancreatic adenocarcinoma, a tumor sharing similar molecular features with ampullary adenocarcinomas (AVCs), above all with the pancreatic-biliary type. We profiled, by in situ hybridization (ISH), miR-21 expression in a series of 26 AVCs, 50 ampullary dysplastic lesions (35 low-grade [LG-IEN] and 15 high-grade [HG-IEN]) and 10 normal duodenal mucosa samples. The same series was investigated by immunohistochemistry for ß-catenin, p53 and HER2 expression. HER2 gene amplification was evaluated by chromogenic in situ hybridization. To validate miR-21 ISH results we performed miR-21 qRT-PCR analysis in a series of 10 AVCs and their matched normal samples. All the normal control samples showed a negative or faint miR-21 expression, whereas a significant miR-21 up-regulation was observed during the carcinogenetic cascade (p < 0.001), with 21/26 (80.8%) of cancer samples showing a miR-21 overexpression. In comparison to control samples, a significant overexpression was found in samples of LG-IEN (p = .0003), HG-IEN (p = .0001), and AVCs (p < 0.0001). No significant difference in miR-21 overexpression was observed between LG-IEN, HG-IEN and AVCs. By qRT-PCR analysis, AVCs showed a 1.7-fold increase over the controls (p = .003). P53 was frequently dysregulated in both dysplastic and carcinoma samples (44 out of 76; 57.9%). A 20% (10/50) of dysplastic lesions and 11% (3/26) of carcinomas were characterized by a nuclear localization of ß-catenin. Only 2 AVCs (7.7%; both intestinal-type) showed a HER2 overexpression (both 2+), which corresponded to a HER2 gene amplification at CISH analysis. This is the first study demonstrating a miRNA dysregulation in the whole spectrum of ampullary carcinogenesis. MiR-21 overexpression is an early molecular event during ampullary carcinogenesis and its levels increase with the neoplastic progression.

PD-L1 overexpression in ampulla of Vater carcinoma and its pre-invasive lesions.

AIMS: PD-1/PD-L1 checkpoint immunotherapy has been proposed recently as a promising treatment in relapsed/refractory disease, used eventually in combination with traditional chemotherapy in different cancer settings. To date, no data are available concerning PD-L1 expression in ampulla of Vater carcinoma and its pre-invasive lesions. METHODS AND RESULTS: We assessed the immunohistochemical expression of PD-L1 in a series of 26 ampullary adenocarcinomas, 50 ampullary dysplastic lesions and 10 normal duodenal mucosa samples. Moreover, in all cases DNA mismatch repair proteins status was investigated. PD-L1 was expressed in seven of 26 (26.9%) invasive carcinomas and three of 50 (6.0%) dysplastic samples. Most of the PD-L1-positive tumours (seven of 10) were intestinal-type and poorly differentiated (G3). The number of PD-L1-positive stromal lymphoid cells was significantly higher in dysplastic and invasive lesions than in the normal samples (P = 0.011). Nineteen dysplastic lesions and eight invasive carcinomas did not show any evident epithelial or stromal PD-L1 expression. Four of the carcinomas were mismatch repair-deficient and two of these were PD-L1-positive. Furthermore, mismatch repair-deficient lesions showed a significantly higher average of PD-L1-positive stromal lymphoid cells than those of neoplastic PD-L1-negative samples (62.8 versus 21.6; P < 0.001). CONCLUSIONS: The present results suggest a role of the PD-1/PD-L1 axis in ampullary adenocarcinomas, and therefore this may also prompt consideration of checkpoint immunotherapy as a novel promising treatment for these tumours.