No this is not possible, and APP is really not the correct place to be considering this. It is a page composition tool rather than a data conversion tool.
You could try the Design Science MathFlow application, but I'm not sure whether that can go from TeX to MathML...
I can confirm Design Science has tools for converting TeX to MathML Presentation format (2.0 or 3.0 from memory). I'm pretty sure MathType includes that functionality.