To investigate the expressions of progesterone receptor a and b in breast invasive ductal carcinoma(IDC) and their associations with clinical and pathological factors and prognosis.

The expressions of PR-a and PR-b in 100 specimens of IDC were detected by immunohistochemistry. The correlations between PR-a, PR-b and characteristics such as ER-α, ER-β, HER-2, Ki-67, axillary lymph node(ALN)metastases, cytological classification, TNM staging and lymphovascular invasion were analyzed, the relationships between PR-a/PR-b ratio and these factors were investigated.

The expression rates of PR-a and PR-b were 55% and 58% respectively. The results showed positive correlation between PR-a and HER-2, Ki-67(P < 0.05), and negative correlation between PR-a and ALN metastases(P < 0.05), ER-β, lymphovascular invasion(P < 0.01), but irrelevant with ER-α, cytological classification, TNM staging. The results also showed that PR-b was negatively correlated with ALN metastases, cytological classification, TNM staging(P < 0.05), lymphovascular invasion, HER-2 and Ki-67(P < 0.01), although irrelevant with neither ER-α nor ER-β. The number of PR-a/PR-b > 1, =1 and <1 was 32(48.5%), 18(27.3%) and 16(24.2%) respectively. In PR-a/PR-b > 1 group, the positive rates of HER-2, Ki-67, high cytological classification, high TNM staging and ALN metastases were higher than PR-a/PR-b≤1 group(P < 0.05).

The expression of PR-b is negatively correlated with HER-2, Ki-67, ALN metastases, cytological classification, TNM staging and lymphovascular invasion. PR-b positive and PR-a/PR-b≤1 can be good indicators of prognosis for IDC.