Establishment of Patient-Derived Xenograft Model

This procedure was approved by the Stanford University's Research Compliance Office on Human Subjects Research and IRB, as well as Stanford's Administrative Panel on Laboratory Animal Care (APLAC). Informed written consent was obtained from the patient and fresh tumor tissue was taken at the time of surgical excision. The sample was placed in ice cold RPMI 1640 medium supplemented with penicillin/streptomycin and 10% heat-inactivated FBS (Invitrogen-Life Technologies, Carlsbad, CA, USA) as previously described by our group [47 (link)]. One to two mm fragments were mixed with LDEV-free Matrigel (BD Biosciences, San Jose, CA, USA) and orthotopically implanted into the MFPs of 5 female NOD SCID mice (NOD. CB17-Prkdc^scid/J, Jackson Laboratory West, Sacramento, CA, USA). Mice were housed in a pathogen-free animal environment. Once established, PDOX tumors were expanded by passaging from mouse to mouse. After a second passage, one PDOX tumor was fixed in formalin and embedded in paraffin for immunohistochemical studies.