Im, interested in studying the NER activity in esophageal cancer tissues. If i will stick to the invitro alkaline comet assay, what should be the substrate DNA.

After reading the literature im bit confused becoz the source of substrate DNA is PBMC/ or any other mammmalian cells exposed to UV rays causing DNA damage in those cells.

However, i want to check the repair activity in cancer tissue, to understand whether the damage is present in the particular DNA of that individual or not. Further, im in dilemma whether its important to check first how much DNA damage is present in a particular DNA of an cancerous tissue and then to check the repair activity.

Alternatively. if repair is high either the damage is more or chances of having mutations is less and is a subject which needs further discussion.

Im looking forward for the easiest/appropriate possible methodology and protocol procedure for understanding DNA repair activity/NER activity in tissue biopsies of cancerous patients vs normal tissues