After this classification the tumors are further divided depending on the different cell types. Most importantly carcinomas, which are characterized by specific cells that commonly found in the internal and external lining parts of the body, for instance, lung, breast, and colon cancer. Cancer formation cascade and cancer causes. Cancer is formed by a mutation in cells. Stem cells divide to produce more cells which are called progenitor cells.
Targeting one or more than of these pathways increases the selectivity of the chemotherapeutic agents as these pathways are only modulated in cancer cells rather than normal cells. Most chemotherapeutic agents work via activation of apoptotic machineries. The frequency of apoptosis could contribute to cell loss in tumors and promote tumor regression (Naik et al., 1996). Apoptosis is accompanied by a series of morphological changes which include cell shrinkage, plasma and nuclear membrane blebbing, organelle relocalization and compaction, chromatin condensation, and production of membrane-enclosed particles containing intracellular material known as apoptotic bodies (Bold et al., 1997). An important fact of Colorectal cancer that it is highly angiogenic , besides it was the first tumor cell type to exhibit significant responses to anti-angiogenic agents both in vitro and in vivo (Mizukami and Chung, 2007).
These growth factors regulate progression to emit intracellular signals, allowing cells to progress through the cell cycle as well as cell growth. Cancerous cells use several methods to acquire the capability to sustain proliferative signaling including the production of growth factor ligand, resulting in autocrine proliferative stimulation. Another method used by cancerous cells is sending signals to stimulate normal cells within the supporting tumor-associated stroma to supply the cancer cells with the necessary growth factors. Cancer cells also showed higher levels of receptor p... ... middle of paper ... ...ks of cancer depicted in this article together dictate the malignant phenotype of cancer. These hallmarks of cancer are fundamental for cancer research, showing the remarkable similarity in the pathologic traits that are ultimate in tumor formation and progression.
Proto-oncogenes are those genes that control normal but essential cell processes that keep cell growth and death in check. Two important categories are apoptosis genes, which regulate cell death, and tumor suppressor genes, which decrease cell propagation 1 . If these genes were mutated to the point where they cannot produce a functioning protein, cell division would continue far past what it was supposed to and unhealthy cells would be allowed to live and continue to multiply. This is what creates a malignant tumor. Certain conditions in the body can also promote the growth of cancer cells.
Cancer is caused by carcinogens. At present, hundreds of chemicals are known to induce cancer. Normally, the body’s cells divide in an orderly way, allowing the body to grow and to heal after injury. Damage or mutations that occur to the proto-oncogenes (POG) and tumour suppresser Genes (TSG) in the genetic material (DNA and RNA) by these carcinogens bring about Cancer, which causes cells to have less control of cell division and differentiation. POGs lead to changed cells or transformed cells and cause excessive cell division.
When the damaged cells won’t die, it becomes a build up of cells that form a mass of tissues called a tumor, mass, or growth. (“Causes.”) Breast cancer will occur when malignant tumors begin to develop inside the breast. These cells can then spread by breaking away the original tumors and by entering blood or lymph vessels, which’ll then branch the tissues throughout the entire body. Cancer cells can travel to other parts of the human body. Cancer begins by damaging tissues and organs, that process that body.
The targeted drug therapy includes taking drugs such as afatinib (also known as BIBW 2992 or gilotrif). First, afatinib works by targeting a protein called epidermal growth factor receptor (EGFR). Then it blocks the EGFR function. Epidermal growth factor receptor is on the surface of both normal cells and cancerous cells. when on the cancerous cells, it will promote the cells’ activity, leading to excessive cell growth and division.
Some of them grow quickly & others grow slowly. The rate of progression of tumor is governed both by mutagenic agents (tumor initiators) and by non mutagenic agents (tumor promoters) that effect gene expression, stimulate cell proliferation and alter the ecological balance of mutant and non mutant cells. The cancer cells frequently move and break from site of the mass or tumor and enter into the bloodstream thereby spreading the disease to other parts of the body and this process is called metastasis (Steward & Kliehues, 2003). Cancer is often defined as a disease that involves changes or mutations in the cell genome. These changes (DNA mutations) produce proteins that disrupt the delicate cellular balance between cell division and quiescence; resulting in cells that keep dividing to form cancers (Hejmadi 2010).
These changes can alter the metabolism and re-engineer the process facilitating the rapid growth and survival of cancer cells through the RAS and mTORC1 pathway. (Rob A. Cairns. et al. 2001 and Chi V Dang. 2012) Lipid, protein... ... middle of paper ... ... complex mechanisms of each type of cancer, there may be different in details and may have to find out more.
Skin cells that lose the ability to grow and divide are called skin cancer. Another name for skin cancer is neoplasia. Skin cancer begins on the outer layer of the skin called the epidermis and is the most common form of cancer in humans. All skin cancers are important but the most commonly seem is the basal cell carcinoma, squamous cell carcinoma, melanoma. These skin cancers happens when the skin starts to grows abnormal skin cells and form a mass called a skin tumor.