Tumor suppressor genes prevent the uncontrolled growth of cells that may result in cancerous tumors. He died shortly thereafter of a cancerous brain tumor. Tumors can be either malignant (cancerous) or benign (non-cancerous). People may experience symptoms regardless of whether the tumor is benign (not cancerous) or cancerous. This overgrowth is more likely to become cancerous than normal endometrial tissue. This can prevent highly mutated cells from becoming cancerous. Many ncRNAs show abnormal expression patterns in cancerous tissues. Ionizing radiation works by damaging the DNA of cancerous tissue leading to cellular death. Radiation therapy works by damaging the DNA of cancerous cells. This localization focuses the radiation exposure on the cancerous lesion. This causes replication of damaged and cancerous cells. Lymph node mapping allows surgeons to track if and where cancerous cells exist. Antibodies attach themselves to the antigens on the surface of cancerous cells. Biopsies are most commonly performed for insight into possible cancerous or inflammatory conditions. The other 40% of cancerous lesions are either hyperechoic or isoechoic.