Table 2.

Possible Mechanisms Underlying Reduced Risk of Estrogen-Related Cancers by Cigarette Smoking

	Cigarette Smoke Constituent
	Nicotine	AhR agonists
Endometrial Cancer	Aromatase inhibition?	AhR/ER cross talk
Endometrioid Ovarian Cancer	Anti-inflammatory effects? Aromatase inhibition	ER/AhR cross talk
Clear Cell Ovarian Cancer	Anti-inflammatory effects?	ER/AhR cross talk?
Thyroid Cancer	Anti-inflammatory effects? Reduction of TSH levels?	ER/AhR cross talk?

? Entry an unlikely or uncertain contributor to an inverse association with cigarette smoking