人类一生大致是20%，美国人比较高，一生接近40%，
在自然界被发现的鲨鱼，癌症发病率 < 0.01%，注意这不是一生的发病率，一生的癌症发病率比这个还要高很多。
AI的总结：
Summary Comparison
| Species | Estimated Lifetime Cancer Risk | Notes |
|---|---|---|
| Humans (U.S.) | ~40% | Common in old age; rising with lifespan |
| Sharks | Likely <1%, possibly <0.1% | Cancer rare but confirmed in several species |
| Other Fish | 0.1–1% | Varies by species and environment (pollution increases rates) |
