Antiretroviral drugs, used to prevent HIV transmission from mother to child, are now believed to cause genetic damage in infants. This damage, leading to an increased risk of developing cancer, makes it highly plausible these children may be diagnosed with the disease in mid and late adulthood.

Two new studies indicate there are cancer-causing effects of transplacental exposure to AZT, an antiretroviral drug. These effects -- like increased incidence of tumors and tumors with genetic changes -- have been demonstrated in mice and rats and seem to be cause for concern in humans too.

"The cumulative mutagenesis data suggest that infants exposed transplacentally to AZT may be at increased risk for cancer as they age," said one researcher, whose findings are published in Environment and Molecular Mutagenesis.

Carrying extra weight is a risk factor for developing breast cancer. But it's not been clear how the timing of weight gain affects this risk. Evidence is mounting, though, and it's now believed that weight gain in adult life is more predictive of breast cancer risk than absolute body weight.

A new study, published in December's International Journal of Cancer, reveals a link between gaining weight in adulthood and an increased risk of breast cancer after menopause.

"We did find some suggestion that weight gain during the 30s and 40s, weight gain since a woman's first pregnancy and weight gain since menopause, especially for women with a longer time since menopause, may all be of importance in relation to postmenopausal breast cancer risk," report the researchers who followed 1,166 women with breast cancer and 2,105 without the disease.

A 70 percent increased risk was found among postmenopausal women who gained more than 60 pounds between age 20 and the onset of menopause. This was in comparison to women who gained less than 20 pounds during the same period of time. Overall, there was a four percent increase in breast cancer risk for each 11-pound increase in adult weight.

The overall cure rate for the 20,000 children diagnosed with cancer in the United States each year is more than 75 percent. Sounds good -- especially when 50 years ago, most children diagnosed with cancer died. But considering that only one in three childhood cancer survivors remain healthy, perhaps this is not such good news.

Thirty years after diagnosis, about 40 percent of survivors have a serious health problem and one-third have multiple problems. Strokes, heart disease, and kidney failure are just a few of the major health concerns that plague many survivors who have entered adulthood.

Doctors have long known that cancer treatments can cause new cancers later in life. But the Childhood Cancer Survivor Study -- the largest ever childhood study of its kind -- shows there are other long-term health problems. Researchers studied 10,000 survivors -- past studies examined 200-300 survivors -- and found these survivors were eight times as likely as their siblings to develop severe and life-threatening conditions. They found survivors of bone tumors, nerve and brain cancer, and Hodgkin's disease faced the highest risk.

The source of these later-in-life health problems vary. Kidney failure may result from damage caused by chemotherapy or radiation or the infections children suffer when their immune systems are weakened. Drugs used to treat infections may also be to blame. Strokes may result from head and chest radiation.

Cancer treatment for people of all ages comes with a price. We buy time, we buy life in exchange for the unknown. But for children -- who stand to live longer than adults -- there is a greater unknown. Sadly, there is a dark side to surviving cancer.