70% of women who develop ovarian cancer have what’s called high-grade serous ovarian carcinoma, or HSC - the ovarian cancer that’s the most malignant. 80,000 women around the world die from HSC each year. That number hasn’t moved in decades despite other advances in cancer treatments. In many cases, this is because women with HSC don’t respond to chemotherapy. After treatment is done, the tumors may come back within a matter of weeks or months. According to Medical News Today,
“Co-senior author and professor David Bowtell, of the Peter MacCallum Cancer Centre in Melbourne, Australia, says our current knowledge is not good enough to make effective clinical decisions about how to deal with ovarian cancer that returns after treatment:
"For decades clinicians around the world have watched HSCs shrink under attack from chemotherapy, before returning aggressively months or years later."
In their paper, he and his colleagues describe how they completely sequenced the genomes of 114 HSC samples from 92 patients and found several clues about how the aggressive cancer changes from initially being vulnerable, to eventually becoming highly resistant to chemotherapy.
The samples were collected from the patients at various stages in disease progression - some at diagnosis, some following successful and unsuccessful treatment, and others immediately after death.
First genetic map of how HSC ovarian cancer evolves in response to chemotherapy
Prof. Bowtell explains that by completely sequencing the genomes from samples taken at different stages of the disease, for the first time we have a map of how HSC evolves under the selective pressure of the chemotherapy.
The results reveal at least four genetic changes that the cancer undergoes to evade initially effective chemotherapy. Prof. Bowtell describes them:
"In two of the mechanisms, cancer cells find a way of restoring their ability to repair damaged DNA and thereby resist the effects of chemotherapy; in another, cancer cells 'hijack' a genetic switch that enables them to pump chemotherapy drugs out of harm's way.
A further mechanism sees the molecular structure of the cancer tissue shift and reshape, such that sheets of 'scar tissue' appear to block chemotherapy from reaching its target."
The researchers say this is the first time that the complex disease has been mapped at this level of detail, and believe their findings point to a range of new strategies that could be used to improve prospects for patients with recurrent ovarian cancer.”
Read the entire article here: http://www.medicalnewstoday.com/articles/294575.php
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