- Oncogenes, which are mutant genes that regulate cell proliferation. Oncogenes allow accelerated proliferation of the mutated cells, resulting in the rapid growth of cancerous tumors.
- tumor suppressor genes, which impede cell proliferation and suppress or prevent cell mutations. Cancer involves inactivation of tumor suppressor genes, allowing replication of mutated cells.
In the TNM system: Cancer patients who require hospice or palliative care generally suffer from advanced disease, which is defined as metastatic spread of the malignancy from the primary site to other areas of the body and/or massive tumor growth at the primary site. The staging of tumors commonly follows the primary tumor, lymph node, and metastasis (TNM) system.