Trace element concentration distributions in breast, lung and colon tissues.

The concentrations of Fe, Cu, Zn and Se in cancerous and benign tissues of breast, lung and intestine (colon) have been determined. In the cases when the element concentration has not been determined in all samples the Kaplan-Meier method has been used for the reconstruction of the original concentration distributions and estimation of the true mean concentrations and medians. Finally, the log-rank test has been applied to compare the elemental concentration distributions between cancerous and benign tissues of the same organ, between cancerous tissues and between benign tissues taken from different organs. Comparing benign and malignant neoplastic tissues, statistically significant differences have been found between Fe and Se concentration distributions of breast as well as for Cu and Zn in the case of lung tissues and in the case of colon tissues for Zn. The concentrations of all elements have been found to be statistically different in cancer tissues as well as in benign ones when comparing the different organs, i.e. groups 'breast-colon' and 'breast-lung'. Concentrations of Fe and Cu have been found to be statistically different in lung and colon cancerous tissues. For benign tissues of lung and colon a statistically significant difference has been found only for Zn.