Definition of cancer. Cancer is a broad range of diseases that form a subset of neoplasms. A tumor is a group of neoplasms that have undergone unregulated growth. The neoplasm serves no physiological function and often forms a nodule. Cancer can result from genetic factors inherited from ancestors. It is possible to be born with a specific genetic mutation or defect in a certain gene that makes the person more likely to develop cancer later in life. Cancer classification nowadays, primary cell types in tumor. One of the important factors in the assortment of a benign or malignant tumor is its potential impact. If a tumor does not have the ability to invade nearby tissues or spread to distant locations and metastasize, then it is benign. Whereas metastatic tumors are malignant, they can affect nearby sites. The rates of development of benign and malignant tumors also differ, benign tumors grow significantly slower than malignant tumors. The appearance of benign tumors is mostly identical, and malignant tumors are often different from those originating from the cell. After this classification, tumors are further divided according to the different cell types. Especially carcinomas, which are characterized by specific cells commonly found in parts of the inner and outer lining of the body, for example lung, breast and colon cancer. Cancer formation cascade and causes of cancer. Cancer is formed by a mutation in cells. Stem cells divide to produce more cells called progenitor cells. These cells divide further and transform into differentiated cells that have specific functions. However, here a mutation occurs which causes the cells to undergo de-differentiation and a series of mutational events occur… middle of paper… a large tumor feeding on blood vessels. When a drug is used to kill cancer cells, there will be some cells that will be resistant to the drug. This causes the surviving cells to multiply and create a completely new colony that is resistant to that specific drug. Symptoms and treatments. The signs and symptoms of cancer are very different and depend on where the cancer is located, how far it has spread and its size. the tumor is. Some tumors can be palpated or seen through the skin, for example a lump on the outer lining can be an indicator of cancer in those locations. Other types of cancer have signs that are less physical in appearance. For example, colon cancers cause symptoms such as constipation, diarrhea, and changes in the shape and color of stool. Bladder or prostate cancer affects bladder function, such as more persistent or unusual urination.