I found an article from National Geographic that described the reasons for this belief and how Carl Luer, one of the leading researchers on this subject, has studied this claim and the results he has found. It was believed for a long time that sharks were one of the few animals that didn't get cancer and as they are one of the oldest creatures on our planet, it seemed like there was something special in the shark's anatomy. To this claim Luer says that while there is something special about the anatomy of sharks, it is not for completely blocking cancer, but for combating it on a small scale. The reason for this misconception was that many sharks had been dissected over the years, for food or medical research, and tumors were never documented. Luer states that all this proves is that sharks have the possibility of getting cancer, however "their incidence is impressively low [which again may be due to] the number of documented cases being low". Nevertheless, Luer has looked to see what exactly makes them able to combat cancer and found that their lack of bone is a key factor. Immune cells are produced by sharks in the spleen, thymus, and the tissue of the gonads and esophagus and replicate as they are in the bloodstream. This creates a more efficient immune response as it takes away the lagging period. There is also evidence that shows that shark cartilage, as well as other animal cartilage, can stop new blood vessels from forming therefore, in the case of tumors cells, can slow cancer cell proliferation.
I found an article about a study that was actually conducted on cancer patients with stage III breast cancer treated with shark cartilage over the course of 3, 6, and 12 weeks.
Table-2.
The level of cytokines and the quality of life in the stage III breast
cancer patients treated for 3 weeks with shark cartilage (n=5) and a
placebo (n=5).
|
||
Subject
|
Before treatment ±SD
|
After treatment ±SD
|
Test group
|
||
Cytokine assay(pg/ml):
IFNγ
IL-4
|
43.37±21.98
53.066±58.40
|
59.710±25.92*
61.748±62.031
|
MTT (SI):
-PHA 5µg/ml
-Shark cartilage extract 150µg/ml
-Shark cartilage extract 50µg/ml
|
1.5545±0.09
1.13±0.09
0.92 ±0.08
|
1.771±0.09
1.217±0.09
0.95 ±0.08
|
Quality of life (%)
|
76.00±12.05
|
79.00±12.86
|
Placebo group
|
||
Cytokine assay(pg/ml):
IFNγ
IL-4
|
42.210±22.14
36.006±30.88
|
42.358±30.7
42.254±33.6
|
MTT (SI):
-PHA 5µg/ml
-Shark cartilage extract 150µg/ml
-Shark cartilage extract 50µg/ml
|
1.325±0.12
0.97±0.09
1±0.1
|
1.771±0.09
0.93±0.07
0.88±0.08
|
Quality of life (%)
|
75.00±2.1 5
|
74.00±8.74
|
*P<0.05; indicates a significant difference in comparison with control group as shown.
SD: Standard Deviation, SI: Stimulation index
|
||
Table-
3. The level of cytokines and the quality of life in the stage III
breast cancer patients a six-week treatment with shark cartilage (n=5)
and a placebo (n=5).
|
||
Subject
|
before treatment ±SD
|
after treatment ±SD
|
Test group
|
||
Cytokine assay(pg/ml):
IFNγ
IL-4
|
39.100±20.88
45.320±26.91
|
78.24±23.38*
46.320±24.86
|
MTT (SI):
-PHA 5µg/ml
-Shark cartilage extract 150µg/ml
|
1.73±0.09
1.007±0.09
|
1.72±0.098
1.089±0.09
|
Quality of life (%)
|
78. 00±16.431
|
82.00±13.038
|
Placebo group
|
||
Cytokine assay(pg/ml):
IFNγ
IL-4
|
39.233±28.49
45.546±41.84
|
39.716±26.77
44.926±46.39
|
MTT (SI):
-PHA 5µg/ml
-Shark cartilage extract 150µg/ml
|
1.018±0.09
0.73±0.09
|
1.50±0.09
1.13±0.09
|
Quality of life (%)
|
76.00 ± 15.00
|
71.00±21.00
|
*P<0.05; indicates a significant difference in comparison with the control group as shown.
SD: Standard Deviation, SI: Stimulation index
|
||
Table-
4. The level of cytokines and the quality of life in the stage III
Invasive ductal carcinoma patients treated for 12 weeks with shark
cartilage (n=5) and a placebo (n=5).
|
||
Subject
|
Before treatment ±SD
|
After treatment ±SD
|
Test group
|
||
Cytokine assay(pg/ml):
IFNγ
IL-4
|
45.82±16.33
68.36±21.34
|
113.40±38.99*
31.992±19.5*
|
MTT (SI):
-PHA 5µg/ml
-Shark cartilage extract 150µg/ml
|
1.64±0.09
1.109±0.09
|
1.74±0.09
1.14±0.09
|
Quality of life (%)
|
82.00±8.3
|
84. 00±13.4
|
Placebo group
|
||
Cytokine assay(pg/ml):
IFNγ
IL-4
|
48.16±33.25
28.46±19.93
|
45.0±34.65
39.58±20.89*
|
MTT (SI):
-PHA 5µg/ml
-Shark cartilage extract 150µg/ml
|
2±0.09
0.89±0.09
|
1.75±0.098
0.97±0.09
|
Quality of life (%)
|
63.00±12.1
|
50.00±23.6*
|
*P<0.05; indicates a significant difference in comparison with control group as shown.
SD: Standard Deviation, SI: Stimulation index
| ||
The results from this study showed that after 3 weeks there was no significant evidence that suggested that shark cartilage had an affect on cancer cell proliferation. Week 6 showed that there was an increase in IFNγ although no significant decrease in IL-4. Week 12 showed an even greater increase in IFNγ with a significant decrease in IL-4. The quality of life of the patients was also measured during this time and it showed that there was a significant decrease in the lives of the patients who had only been receiving the placebo during the test time. The overall conclusion of the study was that shark cartilage was able to stimulate an immune response over a short amount of time and since there were affects for IFN and IL-4, which are important factors for cancer cell progression, that shark cartilage does have the possibility of being helpful for cancer patients, but the researchers feel that 1) the study was too small of a group size to be sure 2) there needs to be a test conducted over a longer time frame and 3) more studies of this nature need to be conducted in order for it to be considered valid.
I also found some articles that talk about the drugs themselves and their affects and side affects if you are interested. The side affects were very minimal consisting of nausea, vomiting, upset stomach, constipation, low blood pressure, dizziness and fatigue. It is possibly safe, but due to lack of test toxicity over a long period of time is unknown.
I mainly wanted to focus on the studies being done that were under scientific and credible supervision, rather than the supplements that are already out there black market style as they are not FDA approved or fully tested.
http://www.cancer.org/Treatment/TreatmentsandSideEffects/ComplementaryandAlternativeMedicine/PharmacologicalandBiologicalTreatment/shark-liver-oil
http://www.cancer.org/Treatment/TreatmentsandSideEffects/ComplementaryandAlternativeMedicine/PharmacologicalandBiologicalTreatment/shark-cartilage
After reading the main research article I feel that there is some potential product here, however, I personally feel that because the results are so small it is not significant enough to really pursue unless more test were done over a larger span of time. But then again I may be biased, more tests means more harm to sharks and they are not at the same mating caliber as mice, so there would be a decrease in the resource before we could really harness a cure and use it. However, other animal cartilage such as cows hold the same valuable ability that sharks have, so again with more credible FDA approved research I feel that this could be a possible preventative measure.
