“Overall, studies have estimated that 1 in 76 women are at risk of developing ovarian cancer in their lifetime, and having endometriosis increases this slightly to 1 in 55,” says Mortlock.
We still don’t know how to predict which endo patients are more likely to develop ovarian cancers, but Mortlock’s recent research gives us a few clues.
The study used genomic data from several large and recent meta-analyses on endometriosis and epithelial ovarian cancer. Unlike previous studies, however, the authors were able to causally associate the genetic components of endometriosis with some types of ovarian cancer.
In simple terms, this means researchers found the genes responsible for endometriosis were driving the development of tissue that increase the risk of developing ovarian cancer, but not the other way around.
This directionality suggests that endometriosis and epithelial ovarian cancer (EOC) are biologically related, and that “a genetic variant’s effect on endometriosis is likely to cause its effect on EOC for the variants highlighted in this study”, according to the authors.
The genetic regions shared by endometriosis and EOC could help experts figure out what mechanisms are driving this causal relationship and what biological pathways might contribute to the risk.
Such research could provide potential drug targets and treatment options for both illnesses, halting their progression.
In the current study, for instance, some shared genetic variants were found in regions known to host hormone-responsive genes.
This suggests hormone regulation might help block the causal pathway between endometriosis and a type of EOC known as clear cell ovarian cancer (CCOC), which is associated with abnormal tissue growth outside the uterus.
The authors also note that cell adhesion pathways were “significantly enriched” for some genetic variations shared between endo and CCOC. This suggests the ability of endometriosis lesions to adhere to tissue might be an important part of disease development for both illnesses.
Endometrioid ovarian cancer (ENOC) was also similarly associated with endometriosis, and, to a lesser extent, high-grade serous ovarian cancer (HGSOC), which is one of the deadliest human cancers with few predictive biomarkers.
Some of the genetic markers for endo and EOC identified in the current study are also shared with other reproductive diseases, like polycystic ovary syndrome and uterine fibroids.
The authors, therefore, suspect the “perturbation of underlying pathways important for the development and regulation of the reproductive and endocrine systems may predispose women to a variety of diseases”, depending on their genetic and environmental risk factors.