It is possible. At RF frequencies, the traces become transmission lines and they have to be impedance controlled. That means that if you bury an RF trace in a 50Ω system, you'll have to design the trace as a stripline, with controlled width of trace and heights of dielectric material both above and below the trace to give a 50Ω stripline. Of course, traces on the outside layers become microstrips, with controlled width of the trace and the height of the dielectric below the trace to maintain the 50Ω.
Yes, it is possible, but it is not an easy task. Depending on the criticality of the design, PCB tolerances may need to be tightly controlled, thus significantly increasing the cost. Plus, troubleshooting a problem PCB batch can be very difficult (you buried a lot of traces). Therefore, you might want to stay away from burying RF traces, if you can and keep all critical components as microstrip.
Now, if you are talking about putting RF traces on a multilayer PCB (and don't intend to bury any traces), this is quite easy. I have done this on multilayer PCBs, including HDI PCBs, quite often with success. You just clear out parts of the inner layers that you need to make the impedances work for you.