A 72-year-old man is diagnosed with a 7 cm primary tumor in his colon, which has spread to the liver. Which of the following features indicates that the tumor is malignant?
AThe spreading of the tumor
BThe size of the tumor
CThe patient's advanced age
DThe location of the primary tumor
AThe spreading of the tumor
BThe size of the tumor
CThe patient's advanced age
DThe location of the primary tumor