Team:Warsaw/Human

Cancer - important social problem

According to many sources cancer remains the main cause of death in both men and women in developped countries. Between 1950 and 1999, death due to cancer arose almost two fold overtaking heart disease, stroke and infectious diseases. For instance cancer currently kill over 100,000 people in Great Britain per year which is more than deaths from heart diseases. The situation in the USA is no better: the death rate from cancer declined by only 5 percent from 1950 to 2005, in contrast with the dropping mortality rates seen for other serious diseases such as stroke.

We now see a dramatic decrease in the number of deaths caused by infectious diseases and heart failures, where as the rates for cancer survival have changed only by little despite of new advances in therapy and treatment.

The emerging patterns in cancer epidemology show that people who live in more deprived areas of the world are more prone to cancer development. However, if the number of deaths from cancer were as low in all social groups as they are in the most affluent ones there would be significantly less deaths caused by cancer every year.

Many scientists are now proposing that a major factor behind the augmenting number of deaths caused by cancer lies in increased human longevity. A number of independent research studies indicate that most of the tumors which contribute to the mortality figures are cancers affecting elderly people. One particular example is the observation that there is a huge increase in the number of women dying from lung cancer in recent years. This type of neoplasm is probably the biggest cause of cancer related deaths amid women exceeding the also rising number of breast cancer cases, which is the second most dreadful killer. With breast cancer, for example, only around 20 percent of patients with metastatic disease — a cancer that has spread outside the breast, live five years or more, a number that has barely changed since the past thirty years.

It is thought that the most efficacious way to tackle cancer related deaths is to educate the public about the risk of the disease. It is believed that more than half of all types of cancer can be prevented by taking simple steps such as switching to a more balanced diet, reducing smoking and alcohol consumption or avoiding intensive exposure to the sun. A large number of deaths is due to the lack of proper education. This leads to the situation in which most of the tumors are diagnosed in their advanced stages when they are more difficult to overcome. At present the situation is most alarming among women, but men are as well failing to seek medical advice soon enough.

The impact of gene therapy

Human genetic engineering may be used to treat genetic disorders, however there is a difference between treating the disease in an individual and germ-line genetic engineering which migth influent the genotype of patient’s descendents.

Gene therapy has been defined as a method that cure disease by replacing, manipulating, or supplementing genes. Therapeutic gene therapy has been defined as the transfer of nucleic acids to somatic cells of a patient to result in therapeutic effect. As compared to traditional medicine, gene therapy offers new possibilities to treat the genetic causes of some diseases. Special hope has been set on treatments for the monogenic diseases. Although this approach still need to be improved, it has been used with some success and scientific breakthroughs continue to move gene therapy towards mainstream medicine. Antisense therapy is not strictly a form of gene therapy, but is a genetically-mediated therapy and is often considered together with classic gene therapy.

Typical gene therapy using an DNA vector which in most cases is a virus. A new gene is inserted into an viral vector, which is used to introduce the modified DNA into a cell. If the treatment is successful, the valid allel will be reintroduce.

Scientists took the logical step of trying to introduce genes straight into human cells, focusing on diseases caused by single-gene defects, such as cystic fibrosis or sickle cell anemia. However, this attempt is much more difficult than modifying simple bacteria, primarily due to the problems involved in carrying large DNA sequence and delivering it to the correct site on the comparatively large human genome. At the present, most gene therapy studies are aimed at cancer and hereditary genetic diseases.

Despite of all benefits there is some concerns around the gene therapy. The trepidations are basically the same as those faced whenever a extraordinary new technology is developed. Such technologies can accomplish great good, but they can also result in harm if applied unwisely.

For the safety of gene therapy, the Weismann barrier is one of the principles of current view on this method. It assume that hereditary information is capable of being carried only from genes to body cells, and reverse process is not possible. In more precise terminology hereditary information is transmitted only from germline cells to somatic cells. The theory is pivotal statement since it has severe implications for human gene therapy. If the Weismann barrier is permeable, then genetic treatments of somatic cells migt actually result in an inheritable change to the genome. The Weismann barrier also affect on our understanding of evolution because of premise that species are not nearly as separable genetically as it has been believed previously.

Reffering to the aforementioned considerations it appears that soma-to-germline feedback should be impossible. However, there are some indications suggesting that the Weissman barrier can be breached. One way to overtake the barrier is the situation if the treatment were misapplied and spread to the testes and therefore would infect the germline against the intentions of the therapy.