Purpose Secondary lymphedema is a frequent complication of breast cancer associated with surgery, chemotherapy, or radiation following breast cancer treatment. The potential contribution of genetic susceptibility to risk of developing secondary lymphedema following surgical trauma, radiation, and other tissue insults has not been studied. Experimental Design To determine if women with breast cancer and secondary lymphedema had mutations in candidate lymphedema genes, we undertook a case - control study of 188 women diagnosed with breast cancer recruited from the University of Pittsburgh Breast Cancer Program (http://www.upmccancercenter.com/breast/index.cfm) between 2000–2010. Candidate lymphedema genes, GJC2 (encoding connexin 47 [Cx47]), FOXC2, HGF, MET, and FLT4 (encoding VEGFR3), were sequenced for mutation. Bioinformatics analysis and in vitro functional assays were used to confirm significance of novel mutations. Results Cx47 mutations were identified in individuals having secondary lymphedema following breast cancer treatment but not in breast cancer controls or normal women without breast cancer. These novel mutations are dysfunctional as assessed through in vitro assays and bioinformatics analysis, and provide evidence that altered gap junction function leads to lymphedema. Conclusions Our findings challenge the view that secondary lymphedema is solely due to mechanical trauma and support the hypothesis that genetic susceptibility is an important risk factor for secondary lymphedema. A priori recognition of genetic risk 1) raises the potential for early detection and intervention for a high risk group, and 2) allows the possibility of altering surgical approach and/or chemo- and radiation therapy, or direct medical treatment of secondary lymphedema with novel connexin modifying drugs. Translational Relevance Secondary lymphedema is a frequent and serious chronic complication of breast cancer treatment. Our finding of four independent mutations in Cx47, including one shared mutation previously reported in primary lymphedema, not only supports these mutations as a genetic risk to the development of secondary lymphedema but raises the likelihood that other genes may contribute to such a genetic risk to secondary lymphedema as well.

Epinephrine and norepinephrine are produced during psychological stress and can directly bind to cells to induce DNA damage. These effects may have more long-lasting consequences such as DNA mutations resulting in an increased potential for cellular transformation and/or tumor progression. This study examined the molecular effects of a chronic (24 h) in vitro exposure to these stress hormones on murine 3T3 cells. Long exposures (24 h) in dose–response experiments with norepinephrine or epinephrine induced significant increases in DNA damage in treated cells compared to that of untreated controls as measured by the alkaline comet assay. Pre-treatment with a blocking agent (the β-adrenergic receptor antagonist propranolol) eliminated this increase in damage. In addition, both norepinephrine and epinephrine increased cellular transformation, as assessed by growth in soft agar, and 3T3 cells pre-treated with either norepinephrine or epinephrine induced a more rapid onset of tumors and more aggressive tumor growth in nude mice. In summary, incubation of 3T3 cells with catecholamines results in long-term DNA damage as measured by increased transformed phenotypes and tumor progression, indicating that they are important mediators of stress effects on genomic instability and vulnerability to tumor formation.

Habitual aerobic exercise has a beneficial effect on many systems of the body, and psychological stress has a negative influence on several of the same systems. One possible pathway is through those systems that account for the detrimental effects of stress; by buffering these harmful effects, exercise may reduce the consequences of stress. This study examined increased resistance of cells to stress-induced oxidative damage as a result of fitness. Forty healthy participants were assigned to either a stress group or a no-stress control group, and measures of stress and oxidative damage were collected. Variation in fitness level across participants was also measured. Oxidative damage increased as a function of stress, but this was not buffered by fitness level. These results should be interpreted with caution because of the small sample size and the limited variability of cardiorespiratory fitness levels in the sample.

<p>PDF file - 170K, Representative LEC microingjections showing dye transfer. Pre-images obtained using DIC and gfp (a,c,e) showing dsred (pink) for reference cell and lucifer yellow dye transfer in blue. LECs electroporated with empty EGFP vector (a,b); WT- hCx47-EGFP (c,d); H409Y-EGFP (e,f). 40x oil, 1.3 n.a.</p>

<p>PDF file - 154K, Mutation chromatograms.</p>

<p>PDF file - 154K, Mutation chromatograms.</p>

<p>PDF file - 170K, Representative LEC microingjections showing dye transfer. Pre-images obtained using DIC and gfp (a,c,e) showing dsred (pink) for reference cell and lucifer yellow dye transfer in blue. LECs electroporated with empty EGFP vector (a,b); WT- hCx47-EGFP (c,d); H409Y-EGFP (e,f). 40x oil, 1.3 n.a.</p>

<p>PDF file - 100K</p>