Ok and why don't we see thousands of bodybuilders with dangerous health problems?
Several reasons.
The time frames can be quite long - we'll see over the next decade as the first generation of guys who probably used high doses of HGH head towards 50 or 60.
Second, oncogene expression would most probably be dependent on various factors; including an individual's 'genetic' predisposition and also exposure (or in this case dose).
Third, these are complex cellular processes - these above papers are based on empirical experimentation -- any such 'link' is certainly not fact. Note that we are talking about hormones that stimulate gene expression - and that is the molecular basis of cancer. There is clearly some risk.