Sharks: 



Naturally 



Just when you thought it was 

 safe to go back in the laboratory 

 . . . scientists are in there study- 

 ing sharks and their potential 

 value in cancer treatment. 



The creatures appear to have a 

 natural resistance to cancer. 



"You just don't find sharks with 

 disease, generally," says Carl Luer, 

 a marine biochemist at Mote 

 Marine Laboratory in Florida. 



A good bit of his work there in- 

 volves exposing sharks, skates 

 and rays to potent chemical 

 carcinogens. 



"We haven't been able to pro- 

 duce anything to even look like 

 the early stage of a tumor," Luer 

 says. 



Exposure during even the initial 

 stages of the embryo, an especially 

 vulnerable period, has failed to 

 produce a tumor. 



Jay Grimes, director of New 

 Hampshire Sea Grant and a pro- 

 fessor at the University of New 

 Hampshire, has studied bacteria 

 associated with shark tissue or 

 cartilage. 



"All tissue in healthy sharks, 

 with the exception of blood, are 

 heavily colonized by a variety of 

 bacteria," he said. "But these 

 bacteria do not cause disease in 

 the shark. 



"The bacteria is apparently liv- 

 ing in a symbiotic relationship we 

 don't understand yet," he says, 

 noting the animal appears af- 

 fected only in the case of undue 

 stress. 



Shark cartilage protein, Grimes 

 explains, appears to have anti- 

 neoplastic qualities, meaning it 

 inhibits the growth of tumors. 



Other research has shown that 

 injections of the cartilage extract 

 have dried up the blood vessels 

 in cancerous tumors of laboratory 

 rats. 



This potential cancer treatment 

 stems from scientists' attempts to 

 inhibit the growth of blood vessels 

 that feed tumors. 



According to a Massachusetts 

 Institute of Technology report, 

 extract from calf cartilage 

 also inhibits blood vessel 

 growth. But for exten- 

 sive experiments, 

 it's hard to get 

 enough extract 

 from the bone- 

 rich skeletons 

 of mammals. 



BY CAR LA BURGESS 



Shark skeletons, on the other 

 hand, are all cartilage. 



Apparently, the research on 

 sharks and cancer is still in its 

 formative stages. 



"The hard part is to keep 

 funded," says Luer. 



He hopes various institutions 

 can eventually work together to 

 advance the research on shark 

 cartilage protein. 



Luer adds that a treatment, 

 when all the bugs are worked out, 

 should be synthesized. 



"We're not looking to rape the 

 environment of all sharks simply 

 to produce this product," he says. 

 "There just aren't enough sharks 

 to support this kind of thing." 



