Loss of BAP1 Expression Is Very Rare in Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Pancreatic cancer is both common and highly lethal and therefore new biomarkers or potential targets for treatment are needed. Loss of BRCA associated protein-1 (BAP1) expression has been found in up to a quarter of intrahepatic cholangiocarcinomas. Given the close anatomical relationship between intrahepatic cholangiocarcinoma and pancreatic ductal adenocarcinoma, we therefore sought to investigate the frequency of loss of BAP1 expression in pancreatic ductal adenocarcinoma. METHODS: The records of the department of Anatomical Pathology Royal North Shore Hospital, Sydney, Australia, were searched for cases of pancreatic ductal adenocarcinoma diagnosed between 1992 and 2014 with material available in archived formalin fixed paraffin embedded tissue blocks. Immunohistochemistry for BAP1 was performed on tissue microarray sections and if staining was equivocal or negative it was confirmed on whole sections. Negative staining for BAP1 was defined as loss of expression in all neoplastic nuclei, with preserved expression in non-neoplastic cells which acted as an internal positive control. RESULTS: Loss of BAP1 expression was found in only 1 of 306 (0.33%) pancreatic ductal adenocarcinomas. This case was confirmed to demonstrate diffuse loss of expression throughout all neoplastic cells in multiple blocks, consistent with BAP1 loss being an early clonal event. All other cases demonstrated positive expression of BAP1. CONCLUSION: We conclude that, in contrast to intrahepatic cholangiocarcinoma, loss of expression of BAP1 occurs very rarely in pancreatic ductal adenocarcinoma. Therefore BAP1 inactivation is unlikely to be a frequent driver abnormality in pancreatic adenocarcinoma.

Bolus or weekly zoledronic acid administration does not delay endochondral fracture repair but weekly dosing enhances delays in hard callus remodeling.

INTRODUCTION: It has been widely assumed that osteoclasts play a pivotal role during the entire process of fracture healing. Bisphosphonates (BPs) are anti-catabolic agents commonly used to treat metabolic bone diseases including osteoporosis, minimizing fracture incidence. Yet, fractures do occur in these patients and the potential for negative effects of BPs on healing has been suggested. We aimed to examine the effect of different dosing regimes of the potent BP zoledronic acid (ZA) on early endochondral fracture repair and later callus remodeling in a normal bone healing environment. METHODS: Saline, a Bolus dose of 0.1 degrees mg/kg ZA or 5 weekly divided doses of 0.02 degrees mg/kg of ZA commenced 1 week post operatively in a rat closed fracture model. Samples at 1, 2, 4 and 6 weeks post fracture were used to analyze initial fracture union, and 12 and 26 weeks post fracture to investigate the progress of remodeling. RESULTS: ZA did not alter the rate of endochondral fracture union. All fractures united by 6 weeks, with no difference in the progressive reduction of cartilaginous soft callus between control and treatment groups over time. ZA treatment increased hard callus bone mineral content (BMC), volume and increased callus strength at 6 and 26 weeks post fracture. Hard callus remodeling commenced at 4 weeks post fracture with Bolus ZA treatment but was delayed until after 6 weeks in the Weekly ZA group. By 12 and 26 weeks, Bolus ZA had equivalent callus content of remodeled neo-cortical bone to the Saline controls, whereas Weekly ZA remained reduced compared to Saline controls at these times (P<0.01). Callus material properties such as peak stress were significantly reduced in both ZA groups at 6 weeks. At 26 weeks, Bolus ZA-treated calluses generated peak stress equivalent to control values, whereas Weekly ZA callus peak stress remained significantly reduced, indicating remodeling delay. CONCLUSIONS: Osteoclast inhibition with ZA does not delay endochondral fracture repair in healthy rats. Bolus ZA treatment increased net callus size and strength at 6 weeks while allowing hard callus remodeling to proceed in the long term, albeit more slowly than control. Prolonged bisphosphonate dosing during repair does not delay endochondral ossification but can significantly affect remodeling long after the drug is ceased.

Using the inflammatory cell infiltrate to estimate the age of human burn wounds: A review and immunohistochemical study.

UNLABELLED: The burn wound healing process, which is reviewed in this paper, has features that differ from the healing of incised cutaneous wounds. This study used immunohistochemical staining and cell counting to examine the inflammatory cell response in biopsy samples of burn wounds from live human subjects obtained at six hours until 23 days after injury in order to determine how the age of a burn could be estimated. Acute inflammatory cells predominated in samples taken six hours to two days after injury. However, neutrophils were often minimal in early samples or could be present late. Elevated numbers of macrophages tended to be encountered from days 2 to 20, but it was not uncommon to observe a minimal or absent macrophage response. Unexpectedly, there was no trend in the number of lymphocytes. A small study was also made of burn wound samples that had been obtained at post-mortem examination of subjects that died in a fire or up to 77 days after injury from fire. This revealed a similar trend of neutrophil and macrophage accumulation. Additionally, it appeared that an increase in the number of lymphocytes occurred late, from 35 days. IN CONCLUSION: If neutrophils predominate, the wound is probably less than a couple of days old. When macrophages are abundant the wound is probably a few days to weeks old. However, as expected from the review of the literature, the inflammatory cell infiltrate may be low or absent in burn wounds, which can render determination of the age of burn wounds difficult.

Activated protein C prevents inflammation yet stimulates angiogenesis to promote cutaneous wound healing.

Activated protein C (APC) is a serine protease that plays a central role in physiological anticoagulation, and has more recently been shown to be a potent anti-inflammatory mediator. Using cultured human cells, we show here that APC up-regulates the angiogenic promoters matrix metalloproteinase-2 in skin fibroblasts and umbilical vein endothelial cells, vascular endothelial growth factor in keratinocytes and fibroblasts, and monocyte chemoattractant protein-1 in fibroblasts. In the chick embryo chorioallantoic membrane assay, APC promoted the granulation/remodeling phases of wound healing by markedly stimulating angiogenesis as well as promoting reepithelialization. In a full-thickness rat skin-healing model, a single topical application of APC enhanced wound healing compared to saline control. APC-treated wounds had markedly more blood vessels on day 7 and a significantly lower infiltration of neutrophils at days 4 and 7. The broad spectrum matrix metallo-proteinase, GM6001, prevented the ability of APC to promote wound healing. In summary, our results show that APC promotes cutaneous wound healing via a complex mechanism involving stimulation of angiogenesis and inhibition of inflammation. These unique properties of APC make it an attractive therapeutic agent to promote the healing of chronic wounds.

A study of p53 expression in thermal burns of human skin for determination of wound age.

Early expression of p53 protein in thermal burns of guinea pig skin has been reported. This study sought to determine if expression occurred in thermal burns of human skin and if immunohistochemical demonstration of p53 protein could be utilised to distinguish ante-mortem from post-mortem injuries as well as indicating the age of a lesion in the living subject. Biopsy samples were obtained from live patients and post-mortem examinations. Immunohistochemistry was used to demonstrate the presence of p53 protein. Staining was assessed by field counting of epithelial cell nuclei. In live subjects there was a tendency for early (six hour to five day) expression, with peak levels occurring around one to two days. Late samples (13 to 23 days) demonstrated minimal or no expression. In contrast, burn wounds from post-mortem examination demonstrated greater staining for p53 protein in the late (28 to 77 day) samples than in the early ones. It appears that expression of p53 protein may assist in the ageing of ante-mortem, but not post-mortem, burn wounds. This implies that results obtained from live subjects may not be applicable to post-mortem material and that any putative method for determining the age of a wound should be tested in both situations.