These tumors are classified as moderately differentiated. Although malignant cells frequently lose their function, appearance, and properties associated with the normal cells of the tissue of origin, in some cases they can acquire new cellular functions uncharacteristic of the originating tissue. For example, tumors in the non-endocrine tissues sometimes acquire the ability to produce and secrete hormones or other proteins. AFP is a protein that is normally produced during fetal life. It is however re expressed by these tumors.
Tumor simply means abnormal growth.
Frequently this term is incorrectly used interchangeably with cancer. However, tumor may refer to a benign or malignant growth. Both benign and malignant tumors result from abnormal proliferation of cells. Benign tumors are generally associated with a more favorable prognosis, unless their presence causes pressure in critical areas such as the brain. The following table outlines the differences between benign and malignant tumors.