AP BIOLOGY

Detailed explanation-1: -Cancers is the result of loss of multicellular traits; thus, it is a disease of multicellularity. Caveat: Many of the so-called multicellular traits are also expressed by unicellular organisms and their loss can result in cancer-like mutants.

Detailed explanation-2: -Cancer represents a breakdown of molecular mechanisms evolved by multicellular life to impose constraints on cell growth, resulting in more “primitive” proliferative cellular phenotypes.

Detailed explanation-3: -Cancer affects almost every multicellular organism on the tree of life, manifesting in slightly different ways across these species. Cancer-like phenomena involving abnormal proliferation have even been reported in fungi and bacteria.

Detailed explanation-4: -Cancerous tumors spread into, or invade, nearby tissues and can travel to distant places in the body to form new tumors (a process called metastasis). Cancerous tumors may also be called malignant tumors. Many cancers form solid tumors, but cancers of the blood, such as leukemias, generally do not.

Detailed explanation-5: -Genes involved in cancer have pseudo-multicellular and multicellular evolutionary origins rather than pure unicellular evolutionary origin. Ceaseless proliferation is the most characteristic feature of cancer.