There is no consistent single biochemical dividing line between a normal cell and its cancerous counterpart. 

A cancerous cell is a normal cell.

In-effectiveness of the so-called DATE concept can be had from the following fact: Paul Macartney's legendry wife Linda (died  17 April, 1998) was advised to have six-monthly mammography. She followed this advice. After twelve years (i.e. after 23rd screening) her pre-cancer was detected. Her breast was chopped and she was declared cancer-free. Within six months, she was again detected having terminal stage of liver cancer. Therapeutic treatment was applied. She died a very painful death within a year. TIME’s Obituary