engleski

Changes in ER, PR and HER-2 expression between primary and metastatic breast cancer after adjuvant therapy

Primary breast cancer is treated according to its ER, PR and HER-2 receptor statuses. The same parameters are carried out in patients who develop metastatic disease after treatment. Since the receptor status of the metastatic lesions may occasionally change after treatment it is crucial to know how frequently that change can occur1, 2. The aim of the study is to compare the immunohistochemical expression of ER, PR and HER-2 between the primary breast cancer (PBC) and matched metastatic lesions (MML) and find out the degree of discordance. The patients received adjuvant chemotherapy and/or endocrine therapy according to guidelines. ER, PR and HER-2 receptors statuses were retested in metastatic lesions developed after therapy. In 37 patients, discordance in hormone receptor status between PBC and MML was observed in 9 patients (24.3%) and discordance in HER-2 status was observed in 4 patients (10.8%). In average, metastatic lesions occurred after four years (median, range 1-16 years). Among 18 cases of PBC with negative ER and PR, four cases of MML expressed changes in ER (22.2%) and five cases in PR (27.7%). In the same group, in two cases HER-2 status was changed from negative PBC to positive MML (11.1%) and in 1 case from positive PBC to negative MML (5.5%). Three cases with HER-2 positivity in PBC remained positive in MML. 21% of 19 hormone positive PBC changed to hormone negative MML (n=4). ER changed to negative in four cases (21%) while PR changed to negative in six cases (31.6%) but it didn’t influence on overall hormone receptor status. In only one case (5.3%) negative HER-2 became positive in MML. Conclusion: 35% of MML developed after adjuvant treatment expressed discordance in ER, PR and HER-2 status compared with the primary tumor. These findings should to be considered in treatment decision.

breast cancer ; HER2 ; hormone receptors ; lymph node metastases

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