The Significance Of The Expression Of Progesterone Receptor Isoforms A And B In Breast Cancers

Objective: To study the expression of PR-A and PR-B in breast cancers with positive PR and explore the correlation between clincopathological characteristics and the expression of PR-A and PR-B as well as their ratio. The influence of PR-A and PR-B on the prognosis of breast cancer is also discussed.Methods: (1) Paraffin fixing samples of breast cancer tissues with PR positive was collected in the Mammary Surgery of Xiangya Hospital, CSU between March 2000 and October 2003. The expression of PR-A and PR-B was detected by IHC-SP method. (2) Statistical analysis was performed using SPSS software version 13.0.Result: (1) All the positive staining of PR-A and PR-B is located in the cell nucleus, not in the cell membrane and cytoplasm. Amount the 82 PR positive breast cancer patients, PR-A was positive in 73 patients (89%), which was higher than PR-B (69%). Amount 48.8% (40/82) patients, the expression was higher in PR-A than PR-B, While amount 37.8% patients, the expression of PR-A was the same as that of PR-B. There were only 13.4% (11/82) patients having higher expression of PR-B. It infers that PR-A and PR-B lost their co-ordinate expression in PR positive breast cancer and the expression of PR-A is prevalent in PR positive breast cancer.(2)The ratio of PR-A and PR-B correlated with the axillary lymph node metastasis (P＝0.042). There is no correlation between the expression of PR-A and PR-B as well as their ratio PR-A: PR-B and clincopathological characteristics, such as age, tumor size, staging, pathological type and neochemotherapy (p＞0.05).(3)No matter PR-A and the ratio of PR-A and PR-B correlates with the state of ER (P＜0.05), as well as positive expression of C-erbB-2(P＜0.05).(5)There is no significant difference between the expression of PR-A and PR-B and DFS (p＞0.05). DFS was lower in breast cancer with high ratio of PR-A to PR-B than that with low ratio of the two isoforms, which is significantly different. (P＜0.05)Conclusion: (1) All the positive staining of PR-A and PR-B is located in the cell nucleus; PR-A and PR-B lost their co-ordinate expression in PR positive breast cancer, in which the expression of PR-A is prevalent.(2) The ratio of PR-A to PR-B correlates with the axillary lymph node metastasis and the expression of C-erbB-2, which infers that the high ratio of PR-A to PR-B may indicate poor prognosis.(4) The higher ratio of PR-A and PR-B may indicate poorer response to endocrine therapy.