>>79451In 2007, the International Agency on Research on Cancer (IARC) classified "shift work that involves circadian disruption" as "probably carcinogenic to humans" (Group 2A) on the basis of "limited evidence in humans for the carcinogenicity of shift-work that involves night work", and "sufficient evidence in experimental animals for the carcinogenicity of light during the daily dark period (biological night)". This was referring breast cancer in women in particular, on which 9 studies have been published so far, 6 of which were positive, but there are some other sporadic indications for cancer of the endometrium (1 positive study), prostate (3 studies, 2 positive), colon-rectal (3 studies, 1 positive), and non-Hodgkin lymphoma (1 positive study)
