Thank you! I wouldn't stress about receiving a rejection for now. Their acceptance email stated this: "In discussions with classmates who may have also applied to the Summer Fellowship Program, please remind them that acceptance is rolling. We will continue to contact applicants as sponsors inform us of their selections. All applicants will receive an application decision by March 10, 2017."
So anyone reading this thread should still stay positive. We got a whole month to go.
I had prior research in oncology for a few years throughout undergrad and have a strong connection to the institution. I honestly don't know how competitive this MSKCC program is, I learned about it last minute. My understanding is that some projects can be very competitive (interesting derm stuff? rads?) while other projects are less competitive. They give you a list of projects with descriptions but they don't disclose who the PI's are (for good reason). I was a little torn between choosing what I thought would be a more popular project and one where I had zero prior exposure in, and a project which I thought was still interesting but I also had tangential experience in. I did a risk assessment and thought it would be safer to go with the latter option because I could make a stronger case for myself and convince the PI I would be a good fit. The website also kind of mentions how prior experience in that particular field is one of the things they look at.
I wish I had a better idea of the # of applicants they receive and the breakdown for each project. So my advice to you, be sincere, have a genuine interest in the work/oncology as a whole, and be strategic when choosing what to work on. Like I said, I imagine radonc and derm are very competitive.