Here's Why Some Cancers Affect Only Young Women

Pancreatic cancer occurs in several forms and one of them affects only young women. Now how could this be possible, when the pancreas are hardly exposed to sex hormones? This pancreatic cancer is known as "mucinous cyst", which is similar to another mucinous cancer, affecting the ovaries. Mucinous tumors of ovary and pancreas (two dissimilar organs) have remarkable similarities in appearance and the disease course. Also, they affect women between 30 to 40 years. The reasons for this phenomenon are not clear and the current study hopes to provide answers that could pave the way for improved treatments.

The study was conducted by scientists at the University of Geneva (UNIGE) and at the University Hospitals of Geneva (HUG), Switzerland, along with colleagues from the United States and the findings appear in the Journal of Pathology.

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Mucinous Tumors in Brief

Mucinous tumors of the ovary and pancreas typically occur in young women, between 30 and 40 years of age. They appear as large cysts or hollow cavities lined by cells and are filled with fluid. They account for about 3 percent of pancreatic and ovarian cancers. If diagnosed early, can be treated by surgery. However, in a small proportion of cases, the cyst breaks before surgery and cancer cells spread to other sites, which do not respond well to chemotherapy. In such cases, the overall survival of patients is less than a year.

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Similarities between Ovarian and Pancreatic Mucinous Tumors

Using public databases, members of the study team, Kevin Elias and Petros Tsantoulis from UNIGE, together with Intidhar Labidi-Galy and co-leader Ronny Drapkin from University of Pennsylvania have developed a transcriptomic profile (which can identify gene expression in a given tissue).

The research team conducted large scale genetic analysis to identify the gene expression profile of the following tissues

• Normal ovarian and pancreatic tissue
• Tissue from mucinous tumors of ovary and pancreas as well as
• Embryonic germ cells at 6, 7, 11, 16 and 17 weeks of pregnancy

The findings of the analysis revealed some interesting facts

• The gene expression profile of normal ovarian and pancreatic tissue was very different from mucinous tumors of ovary and pancreas
• Genetic profile of mucinous tumors of ovary and pancreas were remarkably similar to that of the embryonic germ cells of the fetus during development in the womb

Thus, the findings of the study suggest that the mucinous tumor cells of ovary and pancreas are similar to the embryonic germ cells.

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Connection between Ovary and Pancreas

The ovary and pancreas are two organs that are situated far apart in the human body and have totally different functions. However, they share a close relationship during the development of the embryo in pregnancy.

During development of the embryo in early pregnancy (4 to 6 weeks), primordial germ cells (cells that give rise to the gametes, namely ova and spermatozoa), travel in the embryo to reach the site where the future ovary will develop. During this migration, they pass behind the future pancreas to reach their destination.

This proximity during embryonic life might explain the link between ovarian and pancreatic mucinous tumors and how this occurs is described below.

Embryonic Germ Cells Get Lost on the Way to the Ovary

During embryonic cell migration to reach the site of the future ovary, some of these cells make unexpected stops at their pancreas and remain there. Several decades later, these lost cells become activated and expressed as cancer, particularly in the presence of other risk factors such as smoking.

Interestingly, while the current study has found a link between the pancreas and ovary, similar cases have been reported elsewhere at other sites during migration of the germ cells, especially in the liver or peritoneum.

"Initially, this work was based on clinical observation," says study leader Dr. Intidhar Labidi-Galy, a researcher at the Translational Research Centre in Onco-haematology at the UNIGE Faculty of Medicine and a physician at the HUG. "As a specialist in ovarian cancer, I came across an article detailing the genetic profile of mucinous tumors of the pancreas. To my great surprise, they had the same genetic alterations as mucinous tumors of the ovary, although these two organs have no direct relationship with each other."

Dr. Kevin Elias, assistant professor of obstetrics and gynecology at Brigham's and Women's Hospital, Boston, USA and first author of the paper, identifies the close links between the two tumours: "We found the same genetic mutations, the same types of victims - young women, often smokers - and, even more surprisingly, ovarian tissue in pancreatic cysts."

Conclusion

The study thus offers interesting insights and takes a new look at mucinous pancreatic tumors.

Finding the origin of the tumor and identifying the genetic alterations may open up new research opportunities and help develop improved and more effective treatments for pancreatic mucinous tumors someday in the future.

In the words of Dr. Labidi-Galy, “For each mutation, what is the best treatment? We are here at the heart of personalized oncology: knowing your enemy in every detail makes it easier to fight him."

Reference:

1. Primordial germ cells as a potential shared cell of origin for mucinous cystic neoplasms of the pancreas and mucinous ovarian tumors - (https://onlinelibrary.wiley.com/doi/abs/10.1002/path.5161)

Source-Medindia