Any anabolic substance in your body may disproportionately stimulate tumor growth. Be it insulin, test, HGH. All depends on the mutations that lead to the cancer. The tumor might even have a mutation that makes it oversensitive to a growth factor that follows out of the test or HGH cascade.
That substances that stimulate growth also stimulate cancer growth is a given.
That substances that stimulate growth also stimulate cancer growth is a given.