PGR and substance dependence: Regarding levels of organochlorine and the expression of biomarkers in adjacent breast tumors, concentrations of organochlorine appeared higher when surrounding hormone-dependent (ERα-positive and PR-positive) tumors (geometric means for total organochlorines in hormone-dependent tumors = 1169.2 ng/g versus hormone-independent tumors = 711.1 ng/g); however, this trend was not statistically significant (Mann–Whitney test, P = 0.379).