Cancer is a disease in the air



23.07.2001 14:39

Once the cancer gets air ... or the question: Why is cancer becoming more and more aggressive?

Dr. Bärbel Adams University communication / media department
University of Leipzig

In the vernacular it is said that in a cancer operation, first of all, the cancer can really breathe, and then things quickly go downhill with the patient. Prof. Dr. Dr. Michael Höckel, director of the Leipzig University Women's Clinic (Trier's Institute) and cancer specialist, cannot confirm this. However, the development of a malignant tumor has something to do with oxygen. With oxygen and the Darwinian principle of natural selection.

In the vernacular it is said that in a cancer operation, first of all, the cancer can really breathe, and then the patient quickly goes downhill. Prof. Dr. Dr. Michael Höckel, director of the Leipzig University Women's Clinic (Trier's Institute) and cancer specialist, cannot confirm this. However, the development of a malignant tumor has something to do with oxygen. With oxygen and the Darwinian principle of natural selection.

Prof. Michael Höckel and Prof. Dr. Peter Vaupel, head of the Institute for Physiology and Pathophysiology at Johannes Gutenberg University Mainz, developed a theory that explains why a malignant tumor becomes more and more aggressive the longer it exists. Clinical results and experimental studies are now available to confirm this theory.

In cervical cancer, the scientists examined the supply of oxygen to the tumor by measuring the oxygen partial pressure. To do this, they used very thin probes that were inserted into the tumor in many places. They found that the partial pressure of oxygen in the tumor was significantly lower than in the healthy starting tissue of the tumor. The tumor cells are therefore not adequately supplied with oxygen, a condition that doctors call hypoxia.
Höckel and Vaupel see the causes of the hypoxia primarily in the chaotic vascular system of the malignant tumor. The usual hierarchy of smaller and larger vessels that ensure an adequate supply of oxygen has given way to an arbitrary arrangement. A sufficient supply of nutrients is no longer guaranteed. The tumor cells in the vicinity of blood-supplied vessels obviously still benefit from their oxygen supply. The cells at a greater distance are particularly hypoxic. Since cancer patients mostly suffer from anemia, the hypoxia is exacerbated.

Usually, persistent severe hypoxia leads to apoptosis, i.e. cell death. Some tumor cells stop dividing but continue to exist. With a certain genetic predisposition, tumor cells manage to survive despite hypoxia and thus to develop their destructive power even more. This happens according to the Darwinian principle of natural selection. A malignant tumor consists of many populations of tumor cells that respond differently to hypoxia. Over time, more and more cells are selected that are able to grow even under hypoxic conditions. "Like weeds," says Prof. Höckel. When these cells finally dominate, the hypoxia in the tumor spreads more and more until it is eventually found throughout the tumor.

The surviving tumor cells are particularly aggressive. Among other things, they have lost the ability to apoptosis and continue to grow in other parts of the body - a prerequisite for the formation of metastases. These contain many more apoptosis-resistant cells than the primary tumor. Since the ability to apoptosis has been lost, late tumors no longer respond to radiation or chemotherapy, in which the cells normally die. The battle with the tumor is lost. "Early detection and treatment are the only chance to defeat cancer!" Warns Prof. Michael Höckel.

What Vaupel and Höckel found for cervical cancer has also been confirmed for other types of tumor, e.g. B. for head and neck tumors, soft tissue sarcomas and prostate carcinomas. The theory as to why the tumor becomes more and more malignant due to hypoxia can therefore be generalized. The hypothesis, first presented in 1996 and last this year in a renowned scientific journal, has meanwhile been recognized by many scientists, and the work is one of the most cited papers on the pathogenesis of malignant tumors.

In the meantime, some aspects of the molecular mechanisms that are relevant for the genesis and progression of malignant tumors are also known. New forms of therapy are emerging. The prospect of a general cure for advanced cancer is still not within reach; this disease is far too complex for that. But every new knowledge about his being brings us a little closer to that.

Dr. Bärbel Adams


Additional Information:

http://www.uni-leipzig.de/%7Eufk/
http://physiologie.uni-mainz.de/


Features of this press release:
Nutrition / health / care, medicine
supraregional
research results
German