Cancer is named from the place it originates. This makes a difference on what type of treatments will be effective. Being diagnosed with cancer of the unknown primary (CUP) means that cancer has been found in the body but the place of origin is unknown.

If later, the place of origin is found then the type of cancer diagnosis changes from an unknown primary to the specific organ or body area that the disease first began.

Some cases of cancer of the unknown primary are unfortunately never found. Physicians will then decide on the best course of treatment based on two factors: The way the cells look under the microscope and which organs are currently involved.

Statistics and Prognosis:

The exact number of cases of this disease is not known. It may be about 2% to 5% of all cancers in the United States. It is found more often among men than among women. The average age of people with this cancer is about 60 years.

This is a very dangerous cancer. Only half of patients will live 9 to 12 months after their cancer is found. There are several reasons why this cancer is so serious. First, most of these are fast-spreading cancers. Second, because the exact type is not known, it is harder for doctors to know what treatment is best. Also, the cancer is often widespread, making it harder to cure.

In recent years, microscopic and other diagnostic techniques have improved dramatically. For this reason, doctors can now determine the primary site in about four out of five cases.

1600 years ago, about 400AD, an inherited form of melanoma began from a genetic mutation that occurred in a single ancestor, according to Glasgow University researchers who traced the genetic mutation back 88 generations. Upon further investigation, a number of Scottish families, presently living in Scotland, as well as Australia, Canada and America, were found to carry the specific genetic mutation that puts them at an increased risk for a certain type of melanoma.

According to the researchers, one in ten patients diagnosed with melanoma have a strong family history of the disease and between 20 to 40 percent of those patients carry a high-risk faulty gene known as CDKN2A. The Scottish mutation in this gene is known as M53I. With these genetic discoveries, there is hope that gene therapy can be developed to repair damaged genes in cancer cells.

Kidney transplants can save lives. They can also increase the risk of developing a variety of cancers, according to Australian researchers who report a risk 300 percent higher than in the general population.

Most cancers developed in kidney transplant patients have a known or suspected viral origin, suggesting the weakened immune systems in these patients limit protection against cancer.

"The immunosuppressive drugs transplant patients take lower their ability to fight off infections that can trigger malignancy", the lead researcher said. "We believe the increased incidence of infection leads to the infection that results in cancer." She also notes there is probably an even greater risk of cancer among heart and lung transplant patients because these patients receive more powerful immunosuppressive drugs.

Researchers gathered their findings by comparing the incidence of cancer in 29,000 patients with end-stage kidney disease who received kidney transplants. Data was collected beginning five years prior to transplantation, during dialysis, and after transplantation. Researchers then consulted an Australian registry to identify cancers occurring between the years of 1982-2003. They compared the statistics with the number of cancers seen among transplant patients.

These cancers included melanoma, Kaposi's sarcoma, non-Hodgkin's lymphoma, Hodgkin's disease, leukemia and cancers of the lip, tongue, mouth, salivary gland, esophagus, stomach, colon, anus, liver, gallbladder, lung, connective and other soft tissue, vulva, cervix, penis, eye and thyroid. There was also an increase in nasal cavity and vaginal cancers.

This study has important implications for future immosuppression. Patients should give considerable thought to quality-of-life transplants -- such as face transplants and hand transplants -- and should carefully weigh the risks of weakened immunity. On a brighter note, this study might help prompt research on medication that can selectively target the part of the body responsible for rejecting a transplant. Because right now, medications affect the entire immune system -- and this is what makes patients more prone to developing cancer.