It's ok. You bring up a good point about treatment. And this may get more technical and we could reach a point where I won't have an answer for you.

So first, the X-linked gene is really one of a set of genes mentioned in this paper and what they found was other genes are binding to the X-chromosome inactivated BEND2 gene, this fusion is causing over expression of the pair eventually causing tumors/abnormalities during fetal development. We know women have two copies of the x chromosomes and we see female juveniles are more likely to get astroblastomas; boys can get astroblastomas as well it's just not as common. There were astroblastoma specimens used in this paper from males as well which had the same mutations.

Let's say eventually some scientists find a way to target these genes or cell lines. Would we see girls having better outcomes on the chemotherapy drugs than boys? I would have to say that is the most likely possibility because we see that with other medicines where one group has a better outcome than the others just based on their specific cell biology.

Unfortunately cancers can carry many different types of genetic mutations, whether it be a single deletion of a DNA base, an insertion of a DNA base, a translocation of a chromosome, a reversal of a chromosome, the list goes on. This paper mentions translocations of X-chromosome genes with chromosome number 22, which C22 is found in boys and girls hence how boys can get brain tumors this way as well. Also, there are several RNA mutations that this paper identifies as well.