Melanoma, demethylation, and herv K

Francis Peyton Rous' Co-carcinogenesis hypothesis: that a virus and a carcinogen together cause cancer. (1966 Nobel prize for HPV work)  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2135410/

My co-carcinogenesis takes his further because carcinogens inhibit polymerases.

What I surmise from his hypothesis:

Cancer occurs because a carcinogen inhibits the viral polymerase better than the human polymerase. When a virus infects the same cell as a carcinogen they interact.  Instead of the virus making what it wants in the host the infected cell is transformed into a cancer cell by the carcinogen. 

what causes melanoma? a virus demethylating the DNA or the sun?

Sun exposure and demethylation
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877750/

melanoma and herv-K
https://www.ncbi.nlm.nih.gov/pubmed/23311654

demethylation and melanoma
http://cancerdiscovery.aacrjournals.org/content/5/8/OF6
http://www.sciencedirect.com/science/article/pii/S0014579315010248
https://www.scholars.northwestern.edu/en/publications/clinically-relevant-genes-and-regulatory-pathways-associated-with

melanocortin receptor 1 and melanoma
https://www.ncbi.nlm.nih.gov/pubmed/24460937
https://www.ncbi.nlm.nih.gov/pubmed/25017567

prostate cancer increased risk melanoma
http://www.medscape.com/viewarticle/813922

Hepatitis C (a flavivirus) and prostate cancer
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-55382011000200009

Melanoma 4x higher in parkinon's patients
http://www.medscape.com/viewarticle/806837

Hepatitis C and parkinson's disease risk
https://www.ncbi.nlm.nih.gov/pubmed/25608223

However patients with Hep C appear to have a DECREASED risk of melanoma in sweden
https://www.ncbi.nlm.nih.gov/pubmed/28374973

non epithelial skin cancer does increase with Hep C ?
http://www.oncologynurseadvisor.com/gastrointestinal-cancer/hepatocellular-carcinoma-hepatitis-c-virus-higher-risk-cancers/article/633949/

Lipocalin protein and melanoma
http://www.ncbi.nlm.nih.gov/pubmed/22299829

Lipocalin and West Nile virus
http://www.ncbi.nlm.nih.gov/pubmed/24173226

West nile uses MCR3

Could a different flavivirus use the melanocortin receptor one which would explain the overlap of prostate cancer and parkinson's disease with melanoma? What is going on?????