From tracking the debate over genetic testing for newborns for a couple of conditions that, if unmitigated can cause serious disease - one can actually be treated with genetic therapy(!) - the cost of testing for individual sets of polymorphisms has dropped into the under-$30 range. As it is, a test for many of the SNPs (including almost all the ones that there's some understanding of what conditions they're associated with via GWAS) is under $200 to consumers. The *entire* genome is about $1000 - and IMO pointless as the additional SNPs are unknown.
I have to wonder why genetic screening for cancer-risk isn't on a annual physical checklist - it only needs to be done once (genes don't change) unless there are new SNPs found. I don't see an issue with false positives. Repeating a test is non-invasive. It does change priors when other cancer screening results are being evaluated (I'd expect Baysean logic is the best way to deal with tests that have both false positives and false negatives so better priors get better results - but I'm not MD).
Any thoughts?