TPL2 kinase is a suppressor of lung carcinogenesis.

Lung cancer is a heterogeneous disease at both clinical and molecular levels, posing conceptual and practical bottlenecks in defining key pathways affecting its initiation and progression. Molecules with a central role in lung carcinogenesis are likely to be targeted by multiple deregulated pathways and may have prognostic, predictive, and/or therapeutic value. Here, we report that Tumor Progression Locus 2 (TPL2), a kinase implicated in the regulation of innate and adaptive immune responses, fulfils a role as a suppressor of lung carcinogenesis and is subject to diverse genetic and epigenetic aberrations in lung cancer patients. We show that allelic imbalance at the TPL2 locus, up-regulation of microRNA-370, which targets TPL2 transcripts, and activated RAS (rat sarcoma) signaling may result in down-regulation of TPL2 expression. Low TPL2 levels correlate with reduced lung cancer patient survival and accelerated onset and multiplicity of urethane-induced lung tumors in mice. Mechanistically, TPL2 was found to antagonize oncogene-induced cell transformation and survival through a pathway involving p53 downstream of cJun N-terminal kinase (JNK) and be required for optimal p53 response to genotoxic stress. These results identify multiple oncogenic pathways leading to TPL2 deregulation and highlight its major tumor-suppressing function in the lung.

Vascular and ductal elastotic changes in pancreatic cancer.

This study aims to identify and define the type and frequency of elastotic alterations of vessels and ducts in pancreatic ductal carcinoma (PDAC) and evaluate its diagnostic significance. Representative tissue from 36 Whipple specimens, stained with Verhoeff's Van-Gieson, was studied focusing on the density and distribution of elastic fibers in walls of vessels and ducts, in perivascular and periductal tissue and in tumor stroma. Vessels and ducts within the carcinoma, at tumor periphery and in non-tumoral pancreas were grouped and examined separately. Vimentin and α-SMA immunostains were used for the depiction of fibroblasts and myofibroblasts. Histochemistry revealed mild to severe elastotic changes of vessels and ducts in all examined cases. Vascular and ductal elastosis was more prominent within the tumor and diminished at tumor periphery. In tumor stroma and non-tumoral pancreatic tissue mild or no elastosis was identified. α-SMA+ cells were observed in large numbers in tumor stroma and as a ring around carcinomatous structures. There were scant α-SMA+ cells around elastotic and non-elastotic vessels. Conclusively, vascular and ductal elastosis is a tumor-associated phenomenon in PDAC. Its presence is indicative of benignity acquiring a possible diagnostic role.