Genetic variants of Tgfb1 act as context-dependent modifiers of mouse skin tumor susceptibility.

The human TGFB1 gene is polymorphic, and genetic variants are associated with altered cancer risk. However, human genetic association studies have had variable outcomes because TGFbeta1 action is context-dependent. We used the murine skin model of chemical carcinogenesis in genetic linkage analysis of three independent Mus musculus NIH/Ola x (Mus spretus x M. musculus NIH/Ola)F1 backcrosses, to identify a skin tumor susceptibility locus, Skts14, on proximal chromosome 7. Tgfb1 maps at the peak of linkage. The mouse Tgfb1 gene is polymorphic, resulting in cis-regulated differential allelic mRNA expression between M. spretus and M. musculus in F1 mouse skin. This phenomenon is reflected in differential phospho-SMAD2 levels, downstream of TGFbeta signaling, between these two mouse species. In normal F1 mouse skin, the Tgfb1SPR allele is expressed at higher levels than the Tgfb1NIH allele, and this differential is accentuated by phorbol 12-myristate 13-acetate treatment. In benign F1 papillomas, this imbalance is reversed, possibly by selection against expression of a hyperactive Tgfb1SPR allele in TGFbeta growth-responsive tumors. We demonstrate that skin tumor susceptibility is altered by Tgfb1 gene dosage, but that manifestation of Tgfb1-linked skin tumor susceptibility in M. musculus NIH/Ola x (M. spretus x M. musculus NIH/Ola)F1 backcross mice depends on interactions with another unlinked tumor modifying locus, Skts15, that overlaps Tgfbm3 on chromosome 12. These findings illustrate the power of complex genetic interactions in determining disease outcome and have major implications to the assessment of disease risk in individuals harboring variant TGFB1 alleles.

The participation of volunteers in contemporary palliative care.

Historically, in Australia, individuals with widely differing interests, skills and values have engaged collaboratively, in a voluntary capacity, to establish services to assist persons experiencing particular need or hardship. Gradual recognition and acceptance by the State of its social responsibilities to citizens with various needs in areas of health, welfare, education and others, have seen the provision of a range of statutory services available to all Australians. Volunteer participation in the delivery of modern health services, therefore, is not usual; palliative care is an exception rather than a norm. This article explores the relationship between understandings of death and dying in Western culture and the participation of volunteers in contemporary palliative care. The author presents a view that volunteers provide a distinctive contribution to the quality of care delivery and to enrichment of the social environment of the wider community also. The topic is of relevance to all nurses and especially those involved in the care of dying persons and of their families.