Thursday, April 17, 2014

Dangerous precedent about VIAGRA, its connection to Melanoma!

The risk association of Melanoma with Viagra raises significant fear for those who have no genetic background because Melanoma is still one of the most dangerous and untreatable cancer at advanced stage.  For the scientist, this open the door to further research into gene interactions.
Melanoma is a disease that raises fear in the community given its fatality in advanced stage. In the Untited states it kills close to 9000 lives yearly or more than 10% of affected individual globally.  The gene involved is p16/CDKN2A which encodes for both p16 and p14ARF.   It is worth mentioning that Xeroderma pigmentosum and BRCA2 predispose to this disease.  Also loss of PTEN has been cited for association with Melanoma.    GNAQ/GNA11 has been associated with Uveal Melanoma.  c-KIT has been cited in Lentigo maligna Melanoma.

Viagra, suppressor of the enzyme phosphodiesterase type 5 (PDE5),will block degradation of Cyclic GMP necessary for Erection performance.  What this has to do with PTEN. CDKN2A, and may be p14ARF or BRCA2 becomes of interest.  Other then standard Erection dysfunction, Viagra has been used more chronically in patients who have Pulmonary Hypertension, a silently deadly condition.

This elevated risk of melanoma does not come as a surprise however and more discoveries are upcoming for certain since the Cyclic GMP, like Cyclic AMP are "second messengers" affecting many pathways given their position early in these pathways.  The observation also point to the danger of chronic exacerbations of genes in any pathways.  The reactions occurring in a cell to adjust to excited gene could be deleterious as it can either exacerbate or suppress compensatory pathways, leading to cancers.  Another independent fact is the fact that "second messengers" have been used in the past for Biomarker of chemical molecule activity...and Cyclic GMP is a "messenger", a clear Biomarker of event to come in a cell!
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