I Want to Eat Your Pancreas by Yoru Sumino

An introverted high school boy discovers the secret of his popular classmate Sakura --  she is dying of pancreatic cancer.  He is the only one outside of her family who knows the truth.  The last thing he wants is to become her friend but Sakura's cheerful attitude draws him in . . .



This is a great manga series.  The relationship between the two friends is interesting.  The boy's character growth is believable.  I would recommend this to fans of realistic manga stories.