DDT is one of the few pesticides for which we have some human data. Its persistence lets researchers compare the levels in the blood or fat of women with and without breast cancer. However, some of the studies have serious limitations and, taken together, provide equivocal evidence. There is some evidence that DDT may be a tumor promoter. Another study reported that the estrogenic form of DDT could support the growth of estrogen-dependent breast tumors in mice.
Androgens are male sex hormones.
How anti-androgens affect breast cancer risk is not known. Though atrazine is one of the highest used herbicides in the US, no studies have evaluated the potential for atrazine to cause breast cancer in women exposed to this pesticide. There is sufficient evidence that atrazine induces benign and malignant breast tumors in long-term studies in rats. The mechanism by which atrazine causes breast cancer in rats is not known. Although atrazine is not an estrogen mimic, there is some evidence that it may affect the levels of other hormones.