Advanced Prostate Cancer
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PSA & the Sun

New Australian study [1].

"PSA levels and possibly prostate cancer risk may vary with sun sensitivity and sun exposure, the effects of which might be modified by androgen levels."

The study seems to have started on the premise that:

"Melanoma and prostate cancer may share risk factors."

"There is growing evidence that cutaneous melanoma (CM) and some of its predictors are also predictors of PC risk. Data from 15 cancer registries in different countries showed a relative risk (RR) for PC of 1.27 (95%CI: 1.20–1.33) in men diagnosed with cutaneous melanoma; similar findings have been reported in Australian and Norwegian men (under review) [4, 5]. Solar ultraviolet radiation (UVR), an established predictor for melanoma, may also be a predictor of PC: studies from regions of high ambient UV levels have reported positive associations between UVR and PC risk, while inverse associations were reported in regions of low ambient UV [6–9]. Additionally, other predictors of melanoma risk, such as pigmentary characteristics and variants in pigmentary genes, have been shown to be associated with PC risk, albeit inconsistently. Red-haired participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study were half as likely to develop PC as other men [10]. Results from the Prostate Testing for Cancer and Treatment study (ProtecT) study found that men with a high proportion of variants in pigmentary genes that increase sun sensitivity had greater PC risk than men with no such variants [11]. There is no clear mechanism for the associations between these factors and PC risk."

-Patrick

[1] ncbi.nlm.nih.gov/pubmed/295...

Full Text: journals.plos.org/plosone/a...

PLoS One. 2018 Mar 8;13(3):e0193893. doi: 10.1371/journal.pone.0193893. eCollection 2018.

Associations between sun sensitive pigmentary genes and serum prostate specific antigen levels.

Nair-Shalliker V1,2,3, Egger S1, Chrzanowska A2, Mason R4, Waite L5, Le Couteur D5, Seibel MJ5, Handelsman DJ5, Cumming R2,5,6, Smith DP1,2,7, Armstrong BK2,8.

Author information

1

Cancer Research Division, Cancer Council New South Wales, Sydney, Australia.

2

Sydney School of Public Health, The University of Sydney, Sydney, Australia.

3

Department of Clinical Medicine, Macquarie University, Sydney, Australia.

4

Sydney Medical School, The University of Sydney, Sydney, Australia.

5

Centre for Education and Research on Ageing, Concord Hospital and The University of Sydney, Sydney, New South Wales, Australia.

6

ANZAC Research Institute, The University of Sydney, Sydney, New South Wales, Australia.

7

Menzies Health Institute Queensland, Griffith University, Southport, Queensland, Australia.

8

School of Population Health, University of Western Australia, Perth, Western Australia, Australia.

Abstract

BACKGROUND:

Melanoma and prostate cancer may share risk factors. This study examined the association between serum PSA levels, which is a risk factor for prostate cancer, and variants in some melanoma-associated pigmentary genes.

METHODS:

We studied participants, all aged 70+ years, in the Concord Health and Ageing in Men Project who had no history of prostatitis or received treatment for prostate disease (n = 1033). We genotyped variants in MC1R (rs1805007, rs1805008), ASIP (rs4911414, rs1015362), SLC45A2 (rs28777, rs16891982), IRF4 (rs12203592), TYRP1 (rs1408799), TYR (rs1126809, rs1042602), SLC24A2 (rs12896399), and OCA2 (rs7495174). Generalised linear dominant models with Poisson distribution, log link functions and robust variance estimators estimated adjusted percentage differences (%PSA) in mean serum PSA levels (ng/mL) between variant and wildtype (0%PSA = reference) genotypes, adjusting for age, body mass index, serum 25OHD levels and birth regions (Australia or New Zealand (ANZ), Europe or elsewhere).

RESULTS:

Serum PSA levels were strongly associated with advancing age and birth regions: mean PSA levels were lower in Europe-born (-29.7%) and elsewhere-born (-11.7%) men than ANZ-born men (reference). Lower %PSA was observed in men with variants in SLC45A2: rs28777 (-19.6;95%CI: -33.5, -2.7), rs16891982 (-17.3;95%CI:-30.4,-1.7) than in wildtype men (reference). There were significant interactions between birth regions and PSA levels in men with variants in MC1R (rs1805007; p-interaction = 0.0001) and ASIP (rs4911414; p-interaction = 0.007). For these genes %PSA was greater in ANZ-born men and lower in Europe- and elsewhere-born men with the variant than it was in wildtype men. In a post hoc analysis, serum testosterone levels were increased in men with MC1R rs1805007 and serum dihydrotestosterone in men with ASIP rs1015362.

CONCLUSION:

Men with SNPs in SLC45A2, who have less sun sensitive skin, have lower PSA levels. Men with SNPs in MC1R and ASIP, who have more sun sensitive skin, and were born in ANZ, have higher PSA levels. Androgens may modify these apparent associations of pigmentary genes and sun exposure with PSA levels.

IMPACT:

PSA levels and possibly prostate cancer risk may vary with sun sensitivity and sun exposure, the effects of which might be modified by androgen levels.

PMID: 29518100 DOI: 10.1371/journal.pone.0193893

3 Replies
oldestnewest

I was told by me geneticist that because of my BRCA2 mutation, I stand a slightly higher risk of Melanoma. Although she said the numbers are very small. I wonder if the mechanism of action here are similar to BRCA2 mutation in non-BRCA2 patients.

Reply

I've had plenty of basal and one squamous cell skin cancers. I live in the desert Southwest. I was diagnosed at age 66. My twin, who lives in sun challenged NY State, is free of prostate cancer so far. That might be an argument for purely sun exposure effects, or maybe not.

Reply

Well as I posted several times before... I have both... Pca first and then Melanoma...

Good Luck and Good Health.

j-o-h-n Saturday 03/10/2018 8:22 PM EST

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