Dipeptidyl Peptidase-4 Link With Oral Cancer and Premalignant Lesions

"Participants were told to cease smoking, eating, or drinking before the collection of samples by about half an hour. Obtaining the sample was done by demanding the individual to swallow then incline his head forward to expectorate saliva in a sterile tube for about 3 min. Afterwards the samples were coded by serial numbers then stored at -20°C until being assessed.~Under aseptic circumstances and using plain tubes, 5ml peripheral venous blood samples were collected from all participants by standard venipuncture. Samples were transported to biochemistry laboratory and centrifuged followed by filtration of the clarifying supernatant and then stored at -20ºC"