Tumor Model for Laparoscopy in Pediatric Oncology: Subperitoneal Inoculation of Human Hepatoblastoma Cells in Nude Rats

Abstract BACKGROUND: Minimally invasive surgery (MIS) for diagnostic or even ablative purposes in pediatric oncology is gradually evolving, but little is known about its biological consequences and surgical complications. Especially for hepatoblastoma (HB), no study on the influence of laparoscopy is available yet. A special tumor model could facilitate a variety of investigations. The present study introduces a laparoscopic technique to create subperitoneal metastases of human HB. METHODS: 7 immuno-incompetent (rnu/rnu) rats (mean weight 198 g) received a stab incision in the lower abdomen to insert a 4 mm scope. Under laparoscopic guidance (CO 2 pressure of 1 mmHg, flow of 0.2 l/min) an 18 G needle was introduced, to inject several subperitoneal deposits of the tumor cell suspension (HuH6, 3 × 10 6 in 1 ml of RPMI-1640 medium). Tumor growth was allowed for 6 - 7 weeks and finally the animals were laparoscopically evaluated for peritoneal metastases. Each suspicious lesion was harvested for histology. RESULTS: One animal was investigated after 6 weeks without evidence of tumor growth. After 7 weeks, in 4 out of 6 animals at least one lesion could be detected. Histology revealed HB in all specimens. CONCLUSION: Subperitoneal inoculation of human HB cells in nude rats achieves intraabdominal tumor growth. The present model allows a variety of laparoscopic strategies and their oncological impact to be studied. Thus it may contribute to the development of distinct oncological concepts for MIS in children with HB.