Tag: non infectious diseases

The spread of tumour cells through vascular system (blood, lymph) from the site of formation to other parts of the body is known as metastasis.

The ozone layer is present in the stratosphere above the Earth. The layer of ozone is responsible for the absorption of the harmful ultraviolet radiations from the solar radiations. These radiations are prevented from entering the Earth's atmosphere to prevent the development of skin cancer. The radiations can also damage the eye and other exposed parts of the body. 

Carcinogen is a substance or agent that can cause cells to become cancerous by altering their genetic structure so that they multiply continuously and become malignant. Asbestos, DDT, and tobacco smoke are examples of carcinogens.

Cancer arises from the abnormal, purposeless, and uncontrolled division of cells that then invade and destroy the surrounding tissues.

Cell cycles are regulated by cyclins and Cyclin dependent kinases (CDK). In cancer cells this regulatory mechanism is lost, thus the cells divide or proliferate in an uncontrolled manner after a certain stage, they produce growth factors and respond to them in an autocrine manner. Since, they are the body cells they are not destroyed by the immune system. They are capable of separating from the parent tumor and establishing else where in the body, a process called metastasis.

Saccharin is a artificial sweetener. It is thermostable and remains inert at high temperature. It was discovered in 1879. It helps to control weight and its good for diabetes patients. It was used as sugar substitute in place of sucrose. It has been discontinued because it was considered a carcinogenic agent by FDA.

p53 is a protein is known as  "guardian of genome" because it regulates cellular apoptosis and cellular growth to maintain the integrity of the human genome. It is also known as policeman of oncogenes because it suppresses the mutation and prevents oncogenesis.

Tumour promotion is a process in which an existing tumour is stimulated to grow. The tumour promoter is defined as a chemical, a complex of chemicals, or a biological agent that promotes a later stage of carcinogenesis, called tumour promotion by altering transcription (expression of the genetic information) rather than altering the structure of DNA. A tumour promoter is not involved in the formation of a new tumour.

Lung cancer, also known as lung carcinoma is a malignant lung tumour characterized by uncontrolled cell growth in tissues of the lung. Most cancers which start in the lungs, known as primary lung cancers are carcinomas. Chromium fluoride is a carcinogenous hexavalent chromium which is found in the tap water. It increases the risk of lung cancer, kidney cancer, intestinal cancer etc.

An oncogene is a gene that has the potential to cause cancer. In tumour cells, they are often mutated or expressed at high levels. Activated oncogenes can cause those cells designated for apoptosis (programmed cell death) to survive and proliferate instead. Most oncogenes began as proto-oncogenes which are normal genes involved in cell growth and proliferation or inhibition of apoptosis.