LIFR and Infertility: Women diagnosed with infertility and a control group of fertile women were studied. Researchers took an endometrial biopsy post ovulation to examine LIF and LIF-R expression. No significant differences in LIF/LIF-R was found in the stromal cells but there was a significant reduction in LIF/LIF-R expression in infertile women in epithelial cells. They concluded that LIF and LIF-R are significantly under expressed in epithelial cells of infertile women.