It did not appear that blood provided lactate helped cancer cells over T-cells.
So perhaps Cancer uses LDH to provide the lactate as our body used it to create lactate.
Maybe it is siphoning off the ability for the T cells and then Science provides the needed lactate for the T cels.
here is an article on how LDHA and LDHB fit into the cancer story
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539221/
IIRC, LDH-5 is found in liver and muscles of the skeleton but don’t expect Drs know know anything about the LDH-5/LDH-4 flip. They do seem to know about the LDH-1/LDH-2 flip
What you will see over and over again in studies is that when Total LDH AND/OR there is a composition change it can mean cancer. Drs just seem to think if your LDH Total is normal everything is ok.
You might be able to catch cancer sooner if they paid attention to the flips