"By looking at biological events we have found differences that in future could be used as markers to make a more secure prognosis for women with ovarian cancer", says biologist Karolina Partheen, who has written the thesis.

Ovarian cancer is an unusual disease in Sweden. But despite few persons being afflicted by it, it is the fifth most common cause of women dying of cancer in our country. When tumors are discovered there are a number of factors that influence what type of treatment the patient will undergo. Patients with a similar prognosis can have completely different experiences. This is a big problem within cancer care today, in the treatment of ovarian cancer and in the treatment of other forms of cancer too. The majority of patients undergo insufficient treatment resulting in serious side effects, which represents a big cost for both patients and healthcare.

"In the long run only half of all patients with ovarian cancer respond to the medication they are subjected to. What causes the difference in the way patients respond to antineoplastic agents is not completely clear today, but an underlying cause could be that the tumors have different biological characteristics", says Karolina Partheen.

Cancer is caused by something changing in our gene pool, our genes, which make the body's own cells start dividing uncontrollably. Genes are copied to mRNA that later function as templates from which proteins can be built in a cell. Certain proteins speed up the cell's division time, while others put the brakes on it. So if there is too much or too little of some protein, or if it becomes wrongly constructed, this can lead to cancer.

In her thesis, Karolina Partheen has measured gene copies and how much mRNA or protein has built in different tumors that have the same prognosis. This is done in order to then compare whether there are any differences between tumors from patients who survive or die from the disease.

"One of the most interesting discoveries in the thesis was a profile that seems to be able to distinguish a particular group of patients where everyone survives. In future, if these patients can be detected before treatment with antineoplastic agents, they would be able to get an alternative treatment that results in fewer side effects. Patients that do not correspond to our profile can receive standard treatment with some further medication from the start and tighter follow-ups. In this way the treatment becomes more effective, and side effects are minimised, as well as costs reduced for any over-treatment of patients", says Karolina Partheen.

gupea.ub.gu.se/dspace/handle/2077/10126 and sahlgrenska.se