Primary esophageal and gastro-esophageal junction cancer xenograft models: clinicopathological features and engraftment.

There are very few xenograft models available for the study of esophageal (E) and gastro-esophageal junction (GEJ) cancer. Using a NOD/SCID model, we implanted 90 primary E and GEJ tumors resected from patients and six endoscopic biopsy specimens. Of 69 resected tumors with histologically confirmed viable adenocarcinoma or squamous cell carcinoma, 22 (32%) was engrafted. One of 11 tumors, considered to have had a complete pathological response to neo-adjuvant chemo-radiation, also engrafted. Of the 23 patients whose tumors were engrafted, 65% were male; 30% were early stage while 70% were late stage; 22% received neo-adjuvant chemo-radiation; 61% were GEJ cancers. Engraftment occurred in 18/54 (33%) adenocarcinomas and 5/16 (31%) squamous cell carcinomas. Small endoscopic biopsy tissue had a 50% (3/6) engraftment rate. Of the factors analyzed, pretreatment with chemo-radiation and well/moderate differentiation showed significantly lower correlation with engraftment (P<0.05). In the subset of patients who did not receive neo-adjuvant chemo-radiation, 18/41 (44%) engrafted compared with those with pretreatment where 5/29 (17%, P=0.02) engrafted. Primary xenograft lines may be continued through 4-12 passages. Xenografts maintained similar histology and morphological characteristics with only minor variations even after multiple passaging in most instances.