Ductal adenocarcinoma of the pancreas is almost uniformly lethal as this cancer is invariably detected at an advanced stage and is resistant to treatment. The serine/threonine kinase Mirk/Dyrk1B has been shown to be antiapoptotic in rhabdomyosarcomas. We have now investigated whether Mirk might mediate survival in another cancer in which Mirk is widely expressed, pancreatic ductal adenocarcinoma. Mirk was an active kinase in each pancreatic cancer cell line where it was detected. Mirk knockdown by RNA interference (RNAi) reduced the clonogenicity of Panc1 pancreatic cancer cells 4-fold and decreased tumor cell number, showing that Mirk mediates survival in these cells. Mirk knockdown by synthetic duplex RNAis in Panc1, AsPc1, and SU86.86 pancreatic cancer cells induced apoptosis and enhanced the apoptosis induced by gemcitibine. Mirk knockdown did not increase the abundance or activation of Akt. However, four of five pancreatic carcinoma cell lines exhibited either elevated Mirk activity or elevated Akt activity, suggesting that pancreatic cancer cells primarily rely on Mirk or Akt for survival signaling. Mirk protein was detected by immunohistochemistry in 25 of 28 cases (89%) of pancreatic ductal adenocarcinoma, with elevated expression in 11 cases (39%). Increased expression of Mirk was seen in pancreatic carcinomas compared with primary cultures of normal ductal epithelium by serial analysis of gene expression and by immunohistochemistry. Thus, Mirk is a survival factor for pancreatic ductal adenocarcinoma. Because knockout of Mirk does not cause embryonic lethality, Mirk is not essential for normal cell growth and may represent a novel therapeutic target. (Cancer Res 2006; 66(8): 4149-58)

Rhabdomyosarcoma is the most common sarcoma in children and is difficult to treat if the primary tumor is nonresectable or if the disease presents with metastases. The function of the serine/threonine kinase Mirk was investigated in this cancer. Mirk has both growth arrest and survival functions in terminally differentiating skeletal myoblasts. Maintenance of Mirk growth arrest properties would cause down-regulation of Mirk in transformed myoblasts. Alternatively, Mirk expression would be retained if rhabdomyosarcoma cells used Mirk survival capability. Mirk expression was significant in 12 of 16 clinical cases of rhabdomyosarcoma. Mirk was detected in each rhabdomyosarcoma cell line examined. Mirk was a functional kinase in each of three rhabdomyosarcoma cell lines, where it proved to be more active than in C2C12 skeletal myoblasts. Mirk mediated survival of the majority of clonogenic rhabdomyosarcoma cells. Knockdown of Mirk by RNA interference reduced the fraction of RD and of Rh30 rhabdomyosarcoma cells capable of colony formation 3-to 4-fold in multiple experiments. Depletion of Mirk induced cell death by apoptosis, as shown by increased numbers of terminal deoxynucleotidyl transferase-mediated nick-end labeling-positive cells and by increased binding of Annexin V. Mirk is a stress-activated kinase that mediates expression of contractile proteins in differentiating myoblasts, but Mirk is not essential for muscle formation in the embryo. It is likely that Mirk also facilitates survival of satellite cell-derived rhabdomyoblasts in regenerating skeletal muscle and aids their differentiation. This survival function is maintained in rhabdomyosarcoma, where Mirk may be a novel therapeutic target. (Cancer Res 2006; 66(10): 5143-50)

Hard metal disease (HMD), the interstitial lung disease caused by dusts in the cemented tungsten carbide (WC) industry, has been attributed to cobalt. The rare histologic pattern of giant cell interstitial pneumonia (GIP) is characteristic in HMD. The authors reviewed the history of HMD and 100 cases of HMD that they have seen over 5 decades. GIP was proven in 59; analysis of the lung inorganic particle burden by scanning electron microscopy and energy-dispersive x-ray spectroscopy confirmed HMD in the other 41. Cases have been diagnosed by bronchoalveolar lavage, lung biopsy, and autopsy. Histopathology findings range from focal peribronchiolar inflammation to diffuse interstitial fibrosis and honeycombing. GIP cases in the WC industry reveal elevated concentrations of tungsten in all, but cobalt was detected in only 6 ( approximately 10%). Of the 746 diverse cases in the authors' analytical database, almost all cases with the highest tungsten concentration showed GIP. This study confirms that GIP is effectively pathognomonic for HMD.

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Anastomosing hemangioma (ah) is a rare subtype of primary vascular tumour that can, clinically and radiologically, present similarly to malignant renal tumours such as renal cell carcinoma (rcc) and angiosarcoma. Rarely seen in the genitourinary system, the ah we report here occurred in a 40-year-old male patient diagnosed initially with rcc based on imaging and successfully treated by laparoscopic left radical nephrectomy, with adrenal sparing and perihilar lymph node dissection. The pathologic diagnosis of ah can be challenging on small biopsy specimens; we therefore opine that it is appropriate to excise these lesions to facilitate diagnosis and definitively exclude common renal cancers. However, in this review, we describe some radiologic and pathologic distinctions between ah and malignant tumours.