Can I show my long-term research interests on SOP, which are very important topics but aren't constantly researched yet
Only put something in your SOP as a research goal (short- or long-term) if you can make a credible case that (a) you understand broadly what it's about, and how it fits into your field as a whole, (b) you're capable of achieving it, and (c) the department you're applying to is a good place to do it, or start to do it. As an extreme example, saying you want to cure cancer is a bad idea because it's not realistic. But even saying you want to get into cancer research needs to be supported by evidence that you know something about it, and about the cancer group at the department you're applying to.

If you can't satisfy conditions (a), (b), and (c), it's not necessarily a bad thing, it just means you should be less specific about your goals. You could say, for example, that your end goal is to do research in applied CS, including bioinformatics. Then talk about what you've done already in that area, the skills you want to learn, and why department X is a good place to learn them. Make sure to keep it as focused on CS as possible. The last thing you want the committee to think is "why is this person applying to our department and not stats/applied math/biology?"