Why are some forms of cancer more common in young people and others more common in old people?

I know cancer doesn't discriminate when it comes to age,sex,race etc...but i have heard that certain cancers strike different age groups....why is this so??? why would cancers like lymphoma, leukemia or osteosarcoma mostly affect adolescents, as opposed to cancers like prostate cancer or colon cancer which usually affect people older than 50????

Acute leukemias, brain tumors, bone cancers, retinoblastomas are much more common in children primarily because they are developing. Note, the location of all of these are organs with rapidly dividing cells. Most of these cancers are associated with inherited genetic mutations. This is not a hard rule. Older people can get ALL, lymphomas and, osteosarcoma too. It's just much more rare.

In older people, there is less active cell division. Older people usually accumulated mutations, reduced ability for cell repair and, weaker immune system. Most prostate cancers are very slow growing. In may cases, the patients will die of something else before the prostate cancer. There have been documented cases of colon cancer in the late teens and prostate cancer at age 27. Again, extremely rare.

As a whole, cancer does not discriminate. However, some ethnic groups are far more suspectible to certain cancers than others. Examples:
Ashkenazi Jews have a much higher incidence rate of breast cancer.
Certain Chinese have the highest rate of espogeheal cancer in the World.
Germ cell cancers can only occur in people with that sex organ. In other words, women cannot get prostate or testicular cancer. Men cannot get cervical, vaginal or, ovarian cancer.

Wilms Tumor is a children's cancer. Though I know of one woman in her 30's that just finished treatment.

Wilms generally affects children between the ages of 3 and 4.

I have not known too many teens with leukemia. Mostly elementary school children.

I would contact the American Cancer Society for really detailed info.

The 200 different kinds of cancer have many different causes.

IMMUNE SYSTEMS become weakened by poor nutrition, lack of exercise and reduced oxygen. Once that happens, our body becomes vulnerable to common STRESSORS. Stressors can be environmental, like viruses, heavy metals, pesticides, food additives, electromagnetic waves or pollution. They can be internal things like emotional or job stress, or poisonous people in our lives. Aging is also a contributing factor. So this means:

WEAK IMMUNE SYSTEM + STRESSORS = DISEASE (cancer, diabetes, heart disease, etc.)

Our bodies have 60 trillion--yes, trillion--cells, and there are always some mutating into cancer cells, but a healthy immune system kills them before they have a chance to get a foothold in the body.

It takes a LONG time, usually, or a high level of stressors, to weaken the immune system to the point where it won't do its job, but once cancer has formed, it will generally spread rapidly.

Cancer in young people usually have a genetic link, or a very high level of stressors.