IF you do an excess of iron (chloride), it reduces the CD4 cells and increases the cytotoxic CD8 cells.
I say chlorides because consistently for many studies, notably zinc but applies to Iron, phytates and tannins bind and inhibit the absorption of these two metals, but leave copper alone. Chloride based metals get into the body very quickly.
I'd also look at the mistakes in some studies, different parts of the world have different theories and its possible if you look at enough to see old theories being quoted and not assertions from more recent studies.
The jury is out on what is a good diet to consume for different types of cancer let along a healthy life, its contradictory at best, zinc is good for tackling some cancers, and bad for others. Copper is good for tackling some cancers and not others, and that just looking at two common metals in the diet.
So if the experts knew, I think they would recommend a diet to go on, but they are so steeped in patient privacy they undermine their own authority I think, not to mention come across in general as quite dictatorial.
I have also been messing with some body building amino acids and I liked histdine which is one of the four amino acids that start with zinc, the other three are glutamic acid (glutamate), aspartic acid and cysteine (N-Acetyl Cysteine). Histidine is precursor for histamine which helps immune cells migrate through tissue. Aspartic acid mediates some cysteine based immune responses.
Its also worth looking at vit D, a Wellcome trust study had reverse engineered the human genome about a decade ago and found that most of the Vit D receptors are concentrated around immune system genes (2776 iirc). But you need zinc and cysteine to build the zinc fingers found on these vit D receptors and vit D will switch on some genes and switch off some genes.
Oncologists have access to the testing and measuring equipment, I see no harm if interested in this stuff to get the data from their tests and check their theories against studies found in google scholar, if you wanted piece of mind.
These experts dont always publish their theories so there isnt the transparency, and they dont ask about diet which can be significant in some cases, so they undermine their expertise imo.
And thats before you get into the debate of hackers tampering with results and other things which seem to question the fragile nature of computer security.
And I'm not recommending anything other than question the experts.