Oral shark cartilage does not abolish carcinogenesis but delays tumor progression in a murine model.

Background: Shark cartilage and shark cartilage extracts have been reported to have anti-angiogenic and antineoplastic properties. This study reports the effects of oral administration of powdered shark cartilage on tumor progression in a marine renal tumor model. Materials and Methods: Renal tumors were induced in CBA female mice by a single bolus of IV streptozotocin. 57 mice were fed shark cartilage and the numbers and rate of development of dysplastic convoluted tubules, papillary and solid renal epithelial tumors was compared with 57 control mice over an 88 week follow-up period. Results: In the shark cartilage fed group dysplasia was first observed after 23 weeks (control 19 weeks), papillary tumors after 24 weeks (control 23 weeks) and solid tumors after 55 weeks (control 19 weeks). There was no significant difference in the rate of development of dysplastic tubules between test and control animals. The development of papillary and solid tumors was significantly delayed in the test group. Conclusions: In this tumor model oral shark cartilage delays, but does not abolish, tumor progression.