At the same time cancer rates keep dropping in America, medical experts are beginning to realize what they don't know about this second leading killer of Americans. But they're beginning to catch up, as evidenced by a recent joint report by a group of health agencies, including the International Agency for Research on Cancer and American Cancer Society, identifying 20 "new" causes of cancer, including one you wouldn't expect.

Some of these culprits should be very familiar to you -- formaldehyde, lead, chloroform and PCBs. Then, there's relative newbies, like atrazine and indium phosphide, a binary semiconductor made of indium and phosphorus used in the production of flat-screen TVs.

Probably, the most interesting cancer concern comes straight out of left field, isn't a chemical or substance at all, and it's not the RF energy emitted by mobile phones either.

Think shift work, changing 24/7 schedules that often plays havoc with a patient's circadian rhythms, often leaving them sleep-deprived and vulnerable to a slew of health problems.

International Agency for Research on Cancer Technical Publication No. 42 Free Full Text PDF

Environmental Health Perspectives July 13, 2010 Free PDF Supplement

ScienceDaily July 15, 2010

Chicago Tribune July 15, 2010