Expression of concern.

The Editor in Chief would like to alert readers to the following three articles published in Biological Trace Element Research.

Selenium and Alzheimer's disease: a systematic review.

Preventing Alzheimer's disease (AD) would require knowledge about its etiology to a degree of detail not yet available. The major hurdle in understanding the disease lies in teasing out the various causes and their complex interactions. Since considerable data have accrued showing that the essential trace element selenium (Se) might play different roles in the progression of AD, we conducted a systematic review of the literature regarding Se and AD.

Lead exposure: a contributing cause of the current breast cancer epidemic in Nigerian women.

Breast cancer incidence in Nigerian women has significantly increased during the past three decades in parallel with the rapid industrialization of that country. This suggested that the associated widespread contamination of the soil and of the water supplies by lead (Pb) and other industrial metals was a major contributing cause. Because of its many domestic, industrial, and automotive uses, Pb is of particular concern as it has been shown to promote the development of mammary tumors in murine mammary tumor virus-infected female C3H mice at levels as low of 0.

Selenium and cadmium levels and ratios in prostates, livers, and kidneys of nonsmokers and smokers.

Cadmium (Cd) from cigarette smoke, environmental, and nutritional sources accumulates in the human prostate where it interacts with selenium (Se) in a manner suggesting the formation of a 1:1 Cd-Se-protein complex. At low Cd exposures and adequate Se status, this interaction may be beneficial as it results in the detoxification of Cd. At higher exposures, Cd may weaken or abolish the anticarcinogenic effects of Se and increase prostate cancer risk.