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A neoplasm or tumor is a group of cells that have undergone unregulated growth and will often form a mass or lump, but may be distributed diffusely. [28] [29] All tumor cells show the six hallmarks of cancer. These characteristics are required to produce a malignant tumor. They include: [30] Cell growth and division absent the proper signals
[12] [13] Some neoplasms do not form a tumor; these include leukemia and most forms of carcinoma in situ. Tumor is also not synonymous with cancer. While cancer is by definition malignant, a tumor can be benign, precancerous, or malignant. [citation needed] The terms mass and nodule are often used synonymously with tumor.
The following is a list of cancer types. Cancer is a group of diseases that involve abnormal increases in the number of cells, with the potential to invade or spread to other parts of the body. [1] Not all tumors or lumps are cancerous; benign tumors are not classified as being cancer because they do not spread to other parts of the body. [1]
The criteria for staging can differ dramatically based upon the organ system in which the tumor arises. For example, the colon [22] and bladder cancer [23] staging system relies on depth of invasion, staging of breast carcinoma is more dependent on the size of the tumor, and in renal carcinoma, staging is based on both the size of the tumor and ...
For example, up to half of all tumors have a defective p53 gene. This mutation is associated with poor prognosis, since those tumor cells are less likely to go into apoptosis or programmed cell death when damaged by therapy. Telomerase mutations remove additional barriers, extending the number of times a cell can divide.
A sarcoma is a malignant tumor, a type of cancer that arises from cells of mesenchymal (connective tissue) origin. [1] [2] Connective tissue is a broad term that includes bone, cartilage, muscle, fat, vascular, or other structural tissues, and sarcomas can arise in any of these types of tissues.
For example, a lipoma is a common benign tumor of fat cells , and a chondroma is a benign tumor of cartilage-forming cells (chondrocytes). Adenomas are benign tumors of gland-forming cells, and are usually specified further by their cell or organ of origin, as in hepatic adenoma (a benign tumor of hepatocytes , or liver cells).
Adenocarcinoma [1] (/ ˌ æ d ɪ n oʊ k ɑːr s ɪ ˈ n oʊ m ə /; plural adenocarcinomas or adenocarcinomata / ˌ æ d ɪ n oʊ k ɑːr s ɪ ˈ n oʊ m ə t ə /; AC) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or