Good afternoon doctors. i notice that my stool is the typical brown color when i defecate, but it appears more yellowish when i wipe. is this a concern? could it be an indication of pancreas cancer? or liver or celiac diseases?

Stool color is dependent on the main colorizing agent, deep green bile, and the action of germs in the gut as poop moves though it. Normal colors range through deep greens through yellows to browns depending on how long it stays in the gut & the effect of gut germ metabolism. What you describe is well within the normal range for stool color. This does not indicate any disease.