Establishment of a patient-derived xenograft model

Informed consent was obtained from the participant and a fresh tumor sample was obtained from the tumor tissue of a 70-year old female with confirmed ATC (tumor (T) category 4, lymph node (N) category 1 and with distant metastasis to the lung (M) category 1 –T4N1M1) who underwent surgery at the London Health Sciences Centre. The ATC sample was received 15 minutes after an open biopsy and was kept at 4°C in PBS until engraftment 24hrs post biopsy. The tumor was divided into ~1mm³ pieces and further used for implanting subcutaneously into NOD/SCID/IL2R2γ-/- (NSG) male mice (flank region). Mice were sacrificed using CO₂ asphyxiation when tumors reached a size of 1–1.5 cm and tumors were then dissected. Upon dissection, tumors were dissociated in culture medium (containing DNASE 1 and collagenase/hyaluronidase) [19]. Dissociated tumors were then passaged subcutaneously with five mice per treatment (minimum of 100,000 cells/mouse) in 1:1 Matrigel/PBS to generate the PDX models [19]. Once tumors were palpable in the mice, calipers were used to take periodic measurements.