Mediastinal SS


I am a mother for 13 years boy with Mediastinal Synovial Sarcoma, he had a surgery upfront and had chymotherapy and radiotherapy but the tumor did not respond. Now the doctors are putting him on follow up but I am very afraid and I am trying to seek second opinion, does anyone had a similar experience or any information that may help me


Mediastinal synovial sarcoma is not very common. Was the tumor removed with clear margins during his surgery? It’s important to be followed by sarcoma specialists. According to your profile, you’re located in Egypt?
Oddly, there was a study recently published on mediastinal sarcoma by Dr. Abdel-Rahman from Ain Shams University , Cairo , Egypt:

And another one from Children’s Cancer Hospital:


Thank you for your reply and effort , we are from Egypt, and the doctors in the research you gave are the doctors who had the surgery for my son, unfortunately when they had the surgery the kind of cancer was unknown and they were not able to remove it with good margin and the remaining part did not respond to chymotherapy or radio, Omar my son had a high dose Doxo, infos, radiotherapy. Now children hospital had put him on follow up , I donot know if I should see a second opinion , We saw Dr Andelrahman ( not sure if he is the one with the first article) and we asked him if there is any possible surgery but he said it is too risky. I am not familiar with a lot of scientific vocabularies , trying to catch it, but I seek help from all of you, since I am sure you all can feel me more than any other person. I hope I was able to explain his status.


Can I ask you if you have an idea about EZH2 inhibitor Tazemetostat , and if it was successful with Synovial Sarcoma. Thank you for your information


Tazemetostat was not successful in synovial sarcoma apparently. The company announced in 2016 that : "The synovial sarcoma arm of the Phase 2 trial has been fully enrolled. Although some patients remain on treatment, Epizyme has concluded that the activity of tazemetostat in this cohort is insufficient to continue further investigation of tazemetostat as a monotherapy. Unlike the cancers in the other four arms of the study, synovial sarcoma is characterized by a functional dysregulation of INI1, rather than by a complete loss of INI1."
See the full announcement here:

Can I ask you how you can tell that radiation therapy and chemotherapy did not work? Is there evidence the tumor is growing?

I am not familiar with Egypt but I see that there’s a National Cancer Institute at Cairo University where studies on sarcoma were published. Is it related to the Children’s hospital? May be you could get a second opinion there?


We were in treatment in the children cancer hospital, the tumor is not growing but it did not shrink or show any regression. And that is why they put us on follow up. I donot know a lot scientifically but I feel so worried that I wanted to try anything. Pls if you have any study that may help me such as immunotherapy or else. Another question what do you me by functional dysregulation of INI1, and what is INI1. Maybe stupid questions but I donot know much trying to understand


Your question is not stupid at all and the answer is quite complex and I am not sure how to best explain. Most synovial sarcoma patients have a translocation in the DNA of their synovial sarcoma cells where chromosome 18 and chromosome X have exchanged pieces. This translocation is called SS18-SSX and is believed to cause the disease. It has been shown to change the cell normal program meaning it has an impact on which genes are on and which genes are off via disruption of SWI/SNF, called a remodeling complex which is a group of proteins that affects the way DNA is packaged and which genes are exposed to be transcribed:

One part of SWI/SNF complex is INI1. In synovial sarcoma the complex has a normal INI1 but is disrupted by the translocation protein. On the other hand, some other types of cancer have an abnormal INI1.

EZH2, the target of Tazemetostat is part of another remodeling complex called PRC2 which interacts with SWI/SNF via INI1. So for tumors with abnormal INI1, this interaction is disrupted which is thought to promote tumor growth and proliferation. In the case of synovial sarcoma, the interaction is also believed to be disrupted but due to the translocation:

You can find more information on how Tazemetostat is believed to work here:

I am guessing your son’s doctors want to check how the tumor behaves without treatment. The fact it did not grow nor shrank during treatment may indicate it’s the slow growing type. Does your son’s tumor cause symptoms?


First, I want to thank you over and over for your patience with me, we found out of the presence of the tumor in December 2016, and the symptom was a cough he had and did not go away. A needle biopsy was done and it turned to be malignant cell. But they needed to have a surgical biopsy due to its critical position, and he had a surgery with taking as much of the tumor as possible but some noddles were left due to its position. And it turned to be Synovial Sarcoma. And we started arm D protocol with doxo, infos and radiotherapy. We finished end of September . We had a lot of complications during chymotherapy and radiotherapy and he has a bad ulcer in the esophagus with I guess narrowing of the esophagus too. The cough was the only symptom he had. The doctors refused to have a surgery again since it is too risky for them, I donot know if it can be done in US or Europe. Since as I know it is the best solution after god’s will to remove the tumor. And that is why I started to contact you if I may find anyone that tried a method that may help him, a friend of mine told me about the Tazemetostat so I was checking if it worked with anyone. I heard of immunotherapy but donot know details yet.


I donot think the hospital did genes test, do you think doing it might help in the further treatment


The treatment he received is the conventional first line treatment and the esophagus issue is common with this treatment. When the first line treatment is unsuccessful, other types of chemotherapy may be considered but none is curative. Immunotherapy is still in clinical trials and you can take a look at the different trials available on clinicaltrials.gov. Unfortunately, most clinical trials are conducted in the US or Europe and I don’t think they recruit foreigners.
It’s unlikely that genetic testing (Next Generation Sequencing) would change the treatment plan but not impossible.