Strategys Against Cancer

1523 Words Feb 4th, 2018 6 Pages
The reason for this is due to the poor results of the conventional chemotherapy. The primary cause of this is owing to the lack of selectivity of these drugs. Low molecular weight drugs can enter all types of cells by random diffusion, hence they not only attack tumor cells but they also attack healthy cells with the same potency resulting in severe toxicity. Hence, scientists need to develop strategies to selectively target drugs to tumor cells, to prevent the toxic side effects. One of the most effective strategies to overcome this problem is to exploit the anatomical and pathophysiological abnormalities of tumor tissues such as the enhanced permeation and retention (EPR) effect for anticancer drug delivery. EPR effect is basically the gradual accumulation and retention of certain size molecules (such as nanoparticles, liposomes and macromolecular drugs) in tumor tissues.
2. EPR Effect
When tumor cells proliferate and reach the size of 2mm3, the cells go into a state of hypoxia as the current vasculature fails to provide sufficient oxygen supply. As a result of this, cells start to die and secrete various growth factors that cause the formation of new blood vessels from the existing ones. This process is known as angiogenesis. The new blood vessels formed are irregular in shape and are defective. They have discontinuous epithelium with large fenestrations ranging from 200-2000 nm depending on the tumor type…