Differences in the progesterone receptor contents between familial breast cancers and sporadic breast cancers stratified by patient age

In the present study, we investigated the estrogen (ER) and progesterone re ceptor (PR) contents of familial breast cancers (FBCs) and compared the fin dings with those of sporadic breast cancers, stratified by the patients' ag e. To evaluate the hormone receptor contents of Japanese FBCs, we collected a consecutive series of 250 FBCs and 2533 sporadic breast cancers (SBCs). These patients were divided into the three groups stratified by the patient s' age at initial surgery (group I, under 40 years old; group II, 40-60 yea rs old, group III, over 60 years old). The clinicopathological features of FBCs and SBCs, including ERs and PRs, were analyzed for each group. In all age groups, the PR contents of FBCs were significantly lower than those of SBCs, particularly for group III. In FBCs, the PR content was significantly lower in group III than in groups I or IL In addition, there was a nonsign ificant trend towards a high frequency of ER-positive, PR-negative tumors i n FBC patients aged 60 years and over. These data indicate that the loss of ER function and/or loss of binding capacity of PR to progesterone was asso ciated with some late-onset FBCS..