Tubular, lactating, and ductal adenomas are devoid of MED12 Exon2 mutations, and ductal adenomas show recurrent mutations in GNAS and the PI3K-AKT pathway.

Adenomas of the breast are rare benign tumors although single cases with malignant behavior have been reported. However, the genetic basis of these tumors is unknown. Employing targeted next generation sequencing of 50 cancer-related genes as well as Sanger sequencing, we profiled a cohort of 18 mammary adenomas comprising 9 ductal, 6 tubular, and 3 lactating adenoma. Missense mutations were detected in 8 of the 18 cases (44%). Specifically, five (56%) ductal adenomas and three (50%) tubular adenomas harbored mutated genes. No mutations were detected in lactating adenomas. Three of the nine ductal adenomas showed mutant AKT1 (p.E17K) with two of them harboring an additional GNAS mutation (p.R201C). One case had mutant PIK3CA (p.H1047R) and another case a mutation in GNAS (p.R201C). The three cases of mutated tubular adenomas showed mutations in either MET or FGFR3. Of note, we did not detect copy number changes and none of the cases including tubular adenomas had mutations in exon 2 of MED12. Our results suggest that ductal adenomas are related to papillomas of the breast and screening for mutations in exon 2 of MED12 might help to facilitate differential diagnosis between tubular adenoma and fibroadenoma in difficult cases. Lastly, our data exemplarily demonstrate that mutations in cancer-related genes per se do not indicate malignancy but occur in benign tumors. © 2016 Wiley Periodicals, Inc.

Mutations in genes encoding PI3K-AKT and MAPK signaling define anogenital papillary hidradenoma.

Papillary hidradenoma (a.k.a. hidradenoma papilliferum) is a benign tumor of the anogenital region that almost exclusively arises in middle-aged Caucasian women. These tumors may recur and rare cases of malignant development have been reported. The genetic basis of papillary hidradenoma is currently unknown. Hence, we employed targeted high-coverage next generation sequencing interrogating 50 cancer-related genes and conventional Sanger sequencing to investigate the mutational landscape in a cohort of 15 cases. Additionally, we analyzed the HPV status of these tumors. Thirteen cases (87%) harbored mutations in cancer-related genes. Recurrent mutations in PIK3CA and AKT1 were present in 10 of the cases (67%). One PIK3CA mutated case had a concomitant STK11 mutation. Three cases harbored mutually exclusive mutations in BRAF, APC and ERBB4. The remaining two cases showed no mutations. None of the cases harbored DNA of human papilloma virus. Our results also provide evidence that--just as BRAF V600E mutations in hyperplastic polyps and benign nevi- a mutated driver gene does not imply malignant behavior per se but may set the basis for malignant transformation. The latter point may explain why rare cases of papillary hidradenoma have been reported to take a malignant course. Lastly, our genetic data may suggest treatment avenues beyond conventional surgery for some of these tumors.

High SIRT1 expression is a negative prognosticator in pancreatic ductal adenocarcinoma.

BACKGROUND: Several lines of evidence indicate that Sirt1, a class III histone deacetylase (HDAC) is implicated in the initiation and progression of malignancies and thus gained attraction as druggable target. Since data on the role of Sirt1 in pancreatic ductal adenocarcinoma (PDAC) are sparse, we investigated the expression profile and prognostic significance of Sirt1 in vivo as well as cellular effects of Sirt1 inhibition in vitro. METHODS: Sirt1 expression was analyzed by immunohistochemistry in a large cohort of PDACs and correlated with clinicopathological and survival data. Furthermore, we investigated the impact of overexpression and small molecule inhibition on Sirt1 in pancreatic cancer cell culture models including combinatorial treatment with chemotherapy and EGFR-inhibition. Cellular events were measured quantitatively in real time and corroborated by conventional readouts including FACS analysis and MTT assays. RESULTS: We detected nuclear Sirt1 expression in 36 (27.9%) of 129 PDACs. SIRT1 expression was significantly higher in poorly differentiated carcinomas. Strong SIRT1 expression was a significant predictor of poor survival both in univariate (p = 0.002) and multivariate (HR 1.65, p = 0.045) analysis. Accordingly, overexpression of Sirt1 led to increased cell viability, while small molecule inhibition led to a growth arrest in pancreatic cancer cells and impaired cell survival. This effect was even more pronounced in combinatorial regimens with gefitinib, but not in combination with gemcitabine. CONCLUSIONS: Sirt1 is an independent prognosticator in PDACs and plays an important role in pancreatic cancer cell growth, which can be levered out by small molecule inhibition. Our data warrant further studies on SIRT1 as a novel chemotherapeutic target in PDAC.

Targeting irradiation-induced mitogen-activated protein kinase activation in vitro and in an ex vivo model for human head and neck cancer.

BACKGROUND: Despite new radiotherapeutic strategies, radioresistance in head and neck squamous cell carcinoma (HNSCC) remains a major problem. Preclinical model systems are needed to identify resistance mechanisms in this heterogeneous entity. METHODS: We elucidated the interplay among mitogen-activated protein kinase (MAPK)-inhibition, radiation, and p53 mutations in vitro and in a novel ex vivo model derived from vital human HNSCC samples. HNSCC cell lines (p53WT/mut) were treated with the mitogen-activated protein kinase (MEK)-inhibitor PD-0325901 and subsequently irradiated. Radiosensitization was functionally assessed and evaluated in the ex vivo model. RESULTS: We observed a pronounced irradiation-induced extracellular signal-regulated kinase (ERK) phosphorylation in 2 cell lines, which was independent of their p53 mutation status and associated with PD-0325901-related radiosensitization in a clonogenic assay. Heterogeneity in irradiation-induced ERK phosphorylation and in radiosensitization after MEK-inhibition was also reflected in the ex vivo model. CONCLUSION: We provide experimental evidence for radiosensitizing effects of PD-0325901 in HNSCC. The ex vivo culture technology might offer a promising tool for individualized drug efficacy testing. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2049-E2061, 2016.

TAp63alpha induces apoptosis by activating signaling via death receptors and mitochondria.

TP63, an important epithelial developmental gene, has significant homology to p53. Unlike p53, the expression of p63 is regulated by two different promoters resulting in proteins with opposite functions: the full-length transcriptionally active TAp63 and the dominant-negative DeltaNp63. We investigated the downstream mechanisms by which TAp63alpha elicits apoptosis. TAp63alpha directly transactivates the CD95 gene via the p53 binding site in the first intron resulting in upregulation of a functional CD95 death receptor. Stimulation and blocking experiments of the CD95, TNF-R and TRAIL-R death receptor systems revealed that TAp63alpha can trigger expression of each of these death receptors. Furthermore, our findings demonstrate a link between TAp63alpha and the mitochondrial apoptosis pathway. TAp63alpha upregulates expression of proapoptotic Bcl-2 family members like Bax and BCL2L11 and the expression of RAD9, DAP3 and APAF1. Of clinical relevance is the fact that TAp63alpha is induced by many chemotherapeutic drugs and that inhibiting TAp63 function leads to chemoresistance. Thus, beyond its importance in development and differentiation, we describe an important role for TAp63alpha in the induction of apoptosis and chemosensitivity.