How can a cancer patient with hnscc have their cox-2 enzyme levels evaluated? by blood work, biopsy or both?

Neither: Cox-2 elevation is a function of the tumor characteristics.

Not usual: Cox-2 overexpression needs to be checked from the cancer itself. A genetic mutation in the gene for the enzyme needs to be tested from the individual. However, it is unusual to check for anything related to this enzyme outside of study purposes, meaning that it is not part of a routine workup.