I got this from "Acknowledgment: Receipt of PCOM Philadelphia Campus" email
Fulfillment of the Letter of Recommendation requirement which is as follows:
A letter of recommendation from your pre-health or academic advisor/committee (undergraduate, post-baccalaureate or graduate programs). NOTE: This is the preferred letter of recommendation by the DO Faculty Committee on Admissions.
OR
Three faculty letters of recommendation: Two of those three letters must be from SCIENCE professors (undergraduate, post-baccalaureate or graduate programs).