Even if I do not know the exact answer to your question, I think that there is no fixed rate for this type of metabolic pathway. There are tumors considered "glutaminergic" with a high percentage of glutamine converted to piruvic, and others that do not use this pathway at all. The availability of nutrients in the environment is another influential factor in this issue.

Hello Tomas, My apologies for not responding to your email to thank you. 

Thank you for your feedback. With the renaissance of cancer metabolism there are many questions to answer. I am working on a new hypothesis explaining the Warburg effect and was wondering about glutamine conversion to pyruvate. thanks so much!