PGR and ovarian serous adenocarcinoma: In the stratified analysis by histological types of cancers, progesterone receptor expression was associated with a better DFS/PFS/RFS of unclassified ovarian cancer (n = 11, HR = 0.74, 95% CI = 0.57 to 0.97, P = 0.028, I2 = 57.9%), while no significant association between progesterone receptor expression and DFS/PFS/RFS was detected in serous ovarian cancer patients (n = 4, HR = 0.83, 95% CI = 0.62 to 1.12, P = 0.221, I2 = 62 %).