How does cancer hoodwink the immune system? Placenta may have an answer

Author: Renāte Apse

Who would imagine drawing an equal sign between the placenta and cancer cells? 

Obviously, the structures are not identical, but they both interact with immune system in a similar way. Placenta helps scientists to understand what cancer does to the immune system, so that it can survive. It all began in an unexpected way when a scientist who was pregnant donated blood for research purposes, whose immune cells behaved in a rather different way than normally. Thus Dr. Markovic and his team began to enquire about this observation…

What happens to women’s immune system during pregnancy?

One may wonder – how does a fertilised egg also known as zygote survive, taking into consideration that it is a foreign entity to the immune system (half of the genetic material is different from the mothers’). Theoretically the immune system should attack and destroy the new cell, but it does not. This is explained by the fact that the pregnancy creates a unique immunological condition. However, the unique condition should not be understood as weakened, as some associate pregnancy with immune suppression. In fact, pregnancy is about conservation of the species and thus protect the mother and offspring is fundamental. During pregnancy, the unique condition of mother’s immune system entails higher level of recognition, communication, trafficking and repair.

If one compares immune system before and during pregnancy, there are several indications at the molecular level that demonstrate the different states. If we look at the role of immune system – one of the main functions is to protect the body from foreign organism that may cause infection and disease. How does the immune system manage it? Through cell migration, recognition, response to the pathogen.

At the beginning of pregnancy, there is an increase of inflammatory molecules and cells. High level of inflammatory cytokines are present. These cells compact into the lining of the womb and create an inflammation. Zygote is structured into two primary cell lines: embryoblast and trophoblast (the outer layer). The latter afterwards proliferates and forms cytotrophoblast layer, which consists of two types of cells – syncytiotrophoblast and extravillous trophoblast (EVT). These EVT cells later on anchor the placenta. They act similarly to cancer cells by high-capacity to proliferate, create blood supply and migrate.

Placenta plays a major role during pregnancy, it contains trophoblast cells (form the outer layer of a blastocyst) that prevent immune system to attack the foetus. It also secretes neurokinin B that prevents the immune system to detect the foetus. One may oppose, arguing that the placenta does not prevent immunoglobulin G (IgG) antibodies to cross the placenta… While it may go through the placenta, they do not attack the foetus, but protects it from infections. 

After the inflammation stage, the next 15 weeks are characterised with repressed immune system so that the foetus can grow and develop. There is an increase of anti-inflammatory cells and molecules that protect the foetus (regulatory T cells are fundamental to this anti-inflammatory stage).

How do cancer cells interact with the immune system?

During pregnancy, the trophoblast cells (EVT) play fundamental role in regulating the immune system. There are striking similarities between how cancer cells and trophoblast cells behave. 

Firstly, both have high proliferation. Cancer cells and trophoblast cells have a very high telomerase activity – during pregnancy, high telomerase activity is observed during the first trimester, until the placenta has been formed. Secondly, in both cases – there has to be established a mechanism of nutrition supply. To invade, there has to be enough growth factors, alterations in cell adhesion molecules, and secretion of proteases. Both cells perform this activity, however, trophoblast cells do that in an organised manner without metastasis as one can observe in cancer cells. Third, both cells regulate the immune system. Cancer suppress the immune system with two molecules – PD-L1 and galectin-9. Both molecules inhibit white blood cells and increase the activity of regulatory T cells, which are known to be immunosuppressive. In pregnant women, the levels of PD-L1 and galectin-9 have shown to be elevated. There is a wide acceptance that cancer causes inflammation by secreting cytokines in the surrounding environment or in the blood stream. This allows the cancer to grow and induces to form new blood vessels. Similar mechanism is during placenta development when more blood vessels have to be formed to nurture the foetus. This mechanism is induced by the immune system. It results not merely in immune system ignoring the foreign cells, but even encourage and allow them to grow, proliferate, and develop.

What placenta can teach us about cancer treatment?

The fact that both trophoblast cells and cancer cells entail similar mechanisms, can help scientists to develop drugs that may cure cancer. There are already medications that are used in cancer immunotherapy – with an effect to inhibit PD-L1 (but it has also a side effect – destroying not only the cancer cells but also the healthy cells). The objective is to detect genes that have to be silenced in cancer cells. This research can also help to detect and diagnose ovarian and endometrial cancers. For example, abnormal inflammation and formation of new blood vessels may serve as an indication to ovarian cancer. 

Read More


Article sources:

  1. Mor G, Cardenas I. The immune system in pregnancy: a unique complexity. Am J Reprod Immunol. 2010;63(6):425–433. doi:10.1111/j.1600-0897.2010.00836.x
  2. Holtan SG, Creedon DJ, Haluska P, Markovic SN. Cancer and pregnancy: parallels in growth, invasion, and immune modulation and implications for cancer therapeutic agents. Mayo Clin Proc. 2009;84(11):985–1000. doi:10.1016/S0025-6196(11)60669-1 
  3. Beaman, K. D., Dambaeva, S., Katara, G. K., Kulshrestha, A., & Gilman-Sachs, A. (2017). The immune response in pregnancy and in cancer is active and supportive of placental and tumor cell growth not their destruction. Gynecologic Oncology, 145(3), 476–480.
  4. Scientific American. Can Pregnancy Help Scientists Better Understand Cancer? Available on: [12.04.2019.]
  5. Stanford Medicine. Immune System Changes During Pregnancy are Precisely Timed. Available on: [12.04.2019.]
  6. Medical News Today. What Happens to the Immune System During Pregnancy? Available on: [12.04.2019.]

Photo sources:

  1. Cover source –
  3. Holtan SG, Creedon DJ, Haluska P, Markovic SN. Cancer and pregnancy: parallels in growth, invasion, and immune modulation and implications for cancer therapeutic agents. Mayo Clin Proc. 2009;84(11):985–1000. doi:10.1016/S0025-6196(11)60669-1 
  4. Beaman, K. D., Dambaeva, S., Katara, G. K., Kulshrestha, A., & Gilman-Sachs, A. (2017). The immune response in pregnancy and in cancer is active and supportive of placental and tumor cell growth not their destruction. Gynecologic Oncology, 145(3), 476–480. Pp.478.
154 replies on “ How does cancer hoodwink the immune system? Placenta may have an answer ”
  1. I think other web-site proprietors should take this website as an model, very clean and fantastic user friendly style and design, as well as the content. You are an expert in this topic!

  2. Website We Recommend You completed several nice points there. I did a search on the matter and found most people will have the same opinion with your blog.

  3. Resources like the one you mentioned here will be very useful to me! I will post a link to this page on my blog. I am sure my visitors will find that very useful.

  4. It as difficult to find experienced people in this particular subject, however, you sound like you know what you are talking about! Thanks

  5. This is really interesting, You are a very skilled blogger. I ave joined your feed and look forward to seeking more of your wonderful post. Also, I ave shared your website in my social networks!

  6. You, my friend, ROCK! I found just the info I already searched all over the place and simply couldn at locate it. What a perfect web site.

  7. Viagra cialis levitra order online, where can i order viagra cialis or levitra online without prescription?

  8. It’а†s in point of fact a nice and helpful piece of info. I am glad that you shared this helpful info with us. Please stay us up to date like this. Thanks for sharing.

  9. It as laborious to search out knowledgeable people on this matter, but you sound like you comprehend what you are speaking about! Thanks

  10. Please let me know if you run into anything. I truly enjoy reading your blog and I look forward to

  11. Wonderful work! That is the type of info that should be shared across the web. Shame on Google for no longer positioning this put up higher! Come on over and seek advice from my website. Thank you =)

  12. This very blog is definitely cool and also informative. I have picked helluva interesting advices out of it. I ad love to visit it again and again. Thanks!

  13. That as truly a pleasant movie described in this paragraph regarding how to write a piece of writing, so i got clear idea from here.

  14. There is noticeably a lot to realize about this. I suppose you made certain nice points in features also.

  15. There is obviously a lot to know about this. I think you made various good points in features also.

  16. Wonderful blog! I found it while searching on Yahoo News. Do you have any tips on how to get listed in Yahoo News? I ave been trying for a while but I never seem to get there! Appreciate it

  17. very nice post, i certainly love this website, carry on it

  18. Thanks again for the blog article.Really looking forward to read more. Want more.

  19. Passion in one as true talent is impressive. Writers today usually have little passion about what they write, but you are a unique and great writer. I am glad to see that writers like you exist.

  20. very handful of web-sites that occur to become in depth beneath, from our point of view are undoubtedly effectively worth checking out

  21. Spot up with Spot up with this write-up, I honestly feel this website needs additional consideration. I all apt to be again to learn to read considerably more, many thanks for that information.

  22. It is really a nice and helpful piece of info. IaаАа’б‚Т€ТšаЂаŒаАа’б‚Т€ТžаБТžm glad that you shared this useful information with us. Please keep us informed like this. Thanks for sharing.

  23. Thankyou for this post, I am a big big fan of this internet internet site would like to proceed updated.

  24. You can certainly see your skills in the work you write. The sector hopes for even more passionate writers like you who are not afraid to say how they believe. At all times go after your heart.

  25. Super-Duper website! I am loving it!! Will be back later to read some more. I am taking your feeds also.

  26. This particular blog is no doubt cool additionally factual. I have picked up a bunch of helpful advices out of this amazing blog. I ad love to come back again and again. Thanks a lot!

  27. themselves, especially contemplating the reality that you simply might have completed it if you ever decided. The pointers also served to provide an excellent technique to

  28. wonderful issues altogether, you simply gained a new reader. What would you recommend about your publish that you made some days in the past? Any sure?

  29. I’а†ll right away grab your rss as I can not to find your e-mail subscription hyperlink or newsletter service. Do you have any? Please allow me know in order that I may just subscribe. Thanks.

  30. Normally I don at learn article on blogs, but I would like to say that this write-up very forced me to check out and do so! Your writing style has been surprised me. Thanks, very great article.

  31. Wow, incredible blog layout! How long have you been blogging for? you made blogging look easy. The overall look of your website is wonderful, as well as the content!

  32. Red your site publish and loved it. Have you at any time thought about guest posting on other related blogs related to your blog?

  33. Only a smiling visitant here to share the love (:, btw outstanding design. The price one pays for pursuing a profession, or calling, is an intimate knowledge of its ugly side. by James Arthur Baldwin.

  34. Merely a smiling visitant here to share the love (:, btw outstanding layout. Competition is a painful thing, but it produces great results. by Jerry Flint.

  35. I think this is a real great article post.Really looking forward to read more. Much obliged.

  36. Nice guidelines, many because of the writer. It is comprehensible in my opinion now, the usefulness and importance is overwhelming. Many thanks yet again and best of luck!

  37. Way cool! Some very valid points! I appreciate you writing this article and the rest of the site is also very good.

  38. Wow! Thank you! I always wanted to write on my website something like that. Can I include a portion of your post to my site?

  39. Thanks for sharing, this is a fantastic article.Really looking forward to read more. Much obliged.

  40. Keep up the fantastic work , I read few articles on this web site and I think that your web site is really interesting and contains lots of wonderful info .

  41. Your style is unique in comparison to other people I ave read stuff from. Many thanks for posting when you have the opportunity, Guess I all just book mark this site.

  42. Some times its Some times its a pain in the ass to read what blog owners wrote but this site is rattling user friendly !.

  43. You can definitely see your expertise in the work you write. The arena hopes for more passionate writers like you who aren at afraid to mention how they believe. All the time go after your heart.

  44. Some genuinely nice and useful information on this site, also I conceive the pattern holds good features.

  45. Wolverine, in the midst of a mid-life crisis, pays a visit to an old comrade in Japan and finds himself in the midst of a power struggle.

  46. Your style is so unique compared to other people I ave read stuff from. Thank you for posting when you ave got the opportunity, Guess I will just bookmark this page.

  47. 2kayag I truly appreciate this post. I have been looking all over for this! Thank goodness I found it on Bing. You have made my day! Thank you again

  48. 6DDAKT What as up, I would like to say, I enjoyed this article. This was helpful. Keep going submitting!

  49. VzZKus Merely wanna comment that you have a very nice website , I like the design and style it really stands out.

Leave a Reply

Your email address will not be published.