The presence of endometrial cancer, the most common type of gynecologic cancer, may be revealed through a woman’s reproductive microbiome. A new study reports the association between two types of bacteria, Atopobium vaginae and Porhyromonas species, in women who with endometrial cancer or endometrial hyperplasia. This suggests a novel way for early detection of this cancer for women.
Endometrial cancer occurs when the cells lining the uterus (endometrium) are mutated and grow out of control. The cancer affects the uterus, the hollow organ that supports the growth of the baby when a woman is pregnant. In 2016, the American Cancer Society estimated that around 60,000 new cases of endometrial cancer were diagnosed. Of this, about 17.4 percent will succumb to the disease. For the ones who survive the cancer, pregnancy after cancer treatments may prove difficult and even impossible in cases where the reproductive organs were removed.
The body’s microbiome is gaining more understanding in how it affects our health. We already know that presence of one type of bacteria, Helicobacter pylori, is well linked as to stomach cancer. Presence of other microbes in the system have also been suspected to be the culprit in other health conditions too. However, until now, scientists did not know that bacteria in the female reproductive systems could signal the presence of cancer too.
"We set out to discover whether there is a microbiome component in the malignancy of tumors and if its appearance in patients diagnosed with the disease is distinguishable from that of patients without malignancy," said Marina Walther-Antonio, the study’s lead author.
To investigate, researchers at the Mayo Clinic sampled the microbial colonies found in the female reproductive organs. This included the vagina, cervix, as well as the uterus, fallopian tubes, and ovaries after the scheduled hysterectomies. The cohort consisted of women who were diagnosed with endometrial cancer or endometrial hyperplasia – the precursor condition to the cancer – and women who did not have the cancer.
In women who had the cancer or the precancer, the team found a link with two types of bacteria: Atopobium vaginae and Porhyromonas species. These bacteria were significantly more common in the uterus and vagina of sick women versus women in the control group.
While the team don’t know the mechanism behind the microbe link to endometrial cancer, they suspect that the bacteria A. vaginae may increase inflammation in the endometrium. This could make cells more susceptible to the effects of the Porhyromonas species.
The results require further validation since it was based on only a small number of women (31). However, if the link is confirmed, it could open up a new way for doctors to screen and detect uterine cancer. Furthermore, if the bacteria levels are demonstrated as causative agents, then modifying the growth of these organisms may be an effective way to treat the cancer.
"These findings provide important insights into the etiology or manifestation of the disease with broad implications for biomarker development in the early detection of, and screening for, endometrial cancer," said Walther-Antonio.