Hey so were you accepted to a DO-PhD program or PhD only?
He's got recent posts talking about taking the MCAT in June so I assume he's talking about a PhD-only program
OP, do you want to be an oncologist, or do you want to be a cell biologist and only do research. If the latter, get into a
good PhD program and lab. But this isn't really the forum for that.
If you want to be an oncologist though, it seems to me you are taking the wrong approach. Just for reference, I am a graduate of a combined MD/PhD program but no longer plan for a research career.
First of all, I would discourage you in general from a DO/PhD combined program. Much moreso than medical school, being successful in a research career requires starting to make strong connections in grad school. PI choice for your PhD lab is the most important choice you make in grad school. And honestly DO schools do not have the research infrastructure or the well-connected PIs that you need. MSUCOM is probably the major exception to this.
It is absolutely possible to be a successful researcher and oncologist without a PhD. There are numerous examples out there. But I would argue that DO is not the path to success in this. The pathway for a physician without a PhD to become a successful researcher is to match into a well-ranked residency with good research resources so you can then match into a highly-ranked (in your case oncology) fellowship with lots of successful researchers and significant protected research time. Not just any oncology fellowship is going to do this either--look at a list of the top ~20 med schools and you'll have a decent idea of what you need to aim for. And unfortunately these are the kinds of programs that still discriminate against DOs.