Colorectal cancer rates are rising among younger Americans — the reason behind the jump has become hard for scientists to identify, but the symptoms to watch out are known. Colorectal cancer, which encompasses colon and rectal cancer, is the second leading cause of all cancer-related deaths in the U.S. Last year saw a slight increase in deaths, with just over 53,000 reported. There were also nearly 153,000 new cases of colorectal cancer, the majority of which were in men. While survival rates have improved among older Americans, the incidence rate for people under the age of 55 continues to…