The biological role of smoking, oral contraceptive use and endogenous sexual steroid hormones in invasive squamous epithelial cervical cancer.

For at least twenty years, epidemiological studies have found a correlation between cervical neoplasia and smoking and oral contraceptives. Over the last ten years, laboratory evidence has supported epidemiological findings. One example is the addition of progesterone to human papillomavirus-transfected cervical cells, which has led to oncogenic cell transformation. Very high concentrations of tobacco constituents in cervical mucus, as compared to serum, in smokers provided evidence of a biological role for smoking. It has previously been shown that the S-phase DNA fraction (as a measure of proliferation) was correlated to smoking and serum progesterone. There has been a gap between epidemiological and laboratory findings, as the clinical importance of these correlations have rarely, if ever, been reported. Our recent finding of a positive correlation between serum estradiol/progesterone ratio and length of survival in premenopausal women with invasive cervical cancer might add further knowledge, if confirmed by larger studies. Future studies on tumor markers could elucidate these observations.