Tampons may help predict endometrial cancer

Researchers have found that it is possible to detect endometrial cancer using tumour DNA picked up by ordinary tampons.
The finding is a critical step towards a convenient and effective screening test for endometrial cancer, which starts in the inner lining of the uterus, and is the most common gynecologic malignancy in the US.
The new approach, by researchers at Mayo Clinic, specifically examines DNA samples from vaginal secretions for the presence of chemical "off" switches - known as methylation - that can disable genes that normally keep cancer in check.
"Unfortunately, there is no equivalent to a Pap smear or a mammogram for endometrial cancer," said Jamie Bakkum-Gamez, a gynecologic oncologist at Mayo Clinic and lead author of the study.

"Our goal is to use our findings to develop a tool for the early detection of endometrial cancer that women could use in the comfort of their own homes," Bakkum-Gamez said.
In cancer, tumour suppressor genes are often mutated outright or simply masked with chemical tags or methyl groups known as methylation.

Previous research has shown that a wide variety of genes are turned "off" by such methylation in different types of cancer, leading many investigators to explore how these molecular markers could be used to diagnose the disease.
A small study published in 2004 showed that DNA samples collected from tampons were excessively methylated or hyper-methylated in women with endometrial cancer compared to women without the disease.

However, in the years since then little progress has been made in turning the approach into a practical screening test.
"No one really took that idea and ran with it. We wanted to take this initial study one step further, and use advances in technology to see if we could develop a better method of differentiating between cancerous and benign cells," said Bakkum-Gamez.
Bakkum-Gamez and her colleagues obtained samples from 66 women who were about to undergo a hysterectomy, 38 because of endometrial cancer and 28 due to other indications.
Each woman used an intravaginal tampon to collect vaginal secretions and also underwent endometrial brushing, a procedure that uses a wire brush to scrape cells from the inner lining of the uterus.

The researchers isolated DNA from the samples and then analysed 97 methylation sites along 12 different genes, half initially discovered by members of the research team and half previously reported by other researchers.
They found that methylation was higher in specimens from women with endometrial cancer for 9 of the 12 genes analysed. The results were similar regardless of whether DNA was acquired through a tampon or endometrial brushing.
Despite the encouraging results, the researchers said they need to further refine their method before it can be used clinically.