Path 1 - Lecture 4 - Neoplasia

Neoplasia

Meaning "new growth," it refers to an abnormal mass of tissue whose growth exceeds and is uncoordinated with that of the normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the change.

Tumor

Originally meaning a swelling, this term is now used as a synonym for a neoplasm.

Cancer

A common term for all malignant tumors.

Differentiation

The extent to which neoplastic parenchymal cells resemble the corresponding normal parenchymal cells, both morphologically and functionally.

Metaplasia

A reversible change in which one adult cell type (epithelial or mesenchymal) is replaced by another adult cell type.

Hyperplasia

An increase in the number of cells in an organ or tissue, usually resulting in increased mass of the organ or tissue.

Metastasis

The spread of a tumor to sites that are physically discontinuous with the primary tumor, marking a tumor as unequivocal malignant.

Anaplasia

Literally meaning "to form backward," it refers to a lack of differentiation and is a hallmark of malignancy.

Benign tumor characteristics

Generally characterized by slow growth, well-differentiated cells, being well-circumscribed or encapsulated, and remaining localized to their site of origin.

Malignant tumor characteristics

Characterized by rapid growth, varying degrees of anaplasia (lack of differentiation), invasive growth that destroys surrounding tissue, and the potential to metastasize.

Common human malignancies

The most frequent cancers include lung, prostate/breast, and colorectal carcinomas.

Monster tumors (Teratomas)

Neoplasms that originate from totipotent germ cells (usually in the ovaries or testes) and contain representative cells from all three germ layers: ectoderm, mesoderm, and endoderm.

Most common cause of skin cancers

Exposure to ionizing radiation and specifically ultraviolet (UV) radiation from sunlight.

Tumor suppressor genes (Antioncogens)

Genes that normally prevent uncontrolled cell growth, such as $p53$ and $Rb$, which must be inactivated for certain cancers to develop.

Suffix -oma

A suffix added to the name of the cell type from which a tumor originates to designate a benign tumor.

Suffix -sarcoma

A suffix used to designate malignant tumors arising in solid mesenchymal tissues.

Adenoma

A benign epithelial neoplasm that forms glandular patterns or is derived from glands.

Carcinoma

A malignant neoplasm of epithelial cell origin.

Most common death-related cancer

Lung cancer is the leading cause of cancer-related deaths in both men and women.

Oncogens

Genes whose presence or activation promotes autonomous cell growth in cancer cells.

TNM system of staging

A cancer staging system that evaluates the size and extent of the primary Tumor (T), the presence or absence of regional lymph Node involvement (N), and the presence or absence of distant Metastasis (M).