Jules,
It seems you've been battling with this for quite a while and I wish you good luck with continuing and hopefully getting the upper hand on this.
You are right for sure. The immune system is one of the several mechanisms that have been broken and allow for a multiplication of the problem cells.
It's job is to kill (directly or indirectly) exposing registered patterns.
On the other hands the immune system does probably break down for most of people in their middle age. Autoimmune disorders like arthritis are just a proof of that.
But just a plain immune system problem will not cause cancer.
In any case, this study will not do anything for you in terms of treatment.
Good luck again.