It does not matter in the slightest!
You must write the best book that you can, which means write what interests you! If you try to write what someone else wants, you run into several problems:
- your book is going to be boring, because you are not interested in it and cannot put any emotion into it
- tastes change: by the time you get the book written, send it to the publisher, and they get it printed - it will no longer be "the cutting edge"
- your book will sound too much like the last thing the editor bought, and will be rejected because they want something different
What does matter is that you write a good, solid book that does the following:
- tells an interesting story with emotion (see links below)
- has interesting, realistic characters (see links below)
- is written in a professional style (see links below)
- is submitted in a professional manner (see links below)
