Variations at her2 and hormone receptor status in primary and metastatic sites of breast cancer patients

Evaluation of hormone receptors (ER/PR) and Her2-Neu is important for hormonal and anti-Her2 treatments. The parameters are generally estimated in primary tumors and it is unclear whether re-evaluation of metastatic lesions will be effective during follow-up. Methods: The primary aim of this study was the compare Her2 and HR (ER/PR) status in primary and metastatic tissues of breast cancer patients. HR and Her2 expression in biopsy specimens obtained from primary tumor and their metastatic lesions of 44 breast cancer patients, followed-up during 1995-2010 at Baskent University Hospital were analyzed. Results: Of 44 patients 29.5% were found Her2 (+), 54,5 % ER (+) and 45.4% PR (+) in primary site. Metastatic regions excised or biopsied as following: Bone 31.8% (14/44), liver 27.3% (12/44), skin 25% (11/44), lung 9.1% (4/44), brain 4.5% (2%44), bone marrow 4.5 (2/44), ovaries 4.5% (2/44), stomach, abdominal LAP and pelvic mass 2.3% (3/44). Positification rate of ER status in metastatic sites was detected as 4.5% (2/44), when positive in primary tumors, negatification rate was detected as 20.5%. The positification rate of PR status in metastatic sites, while being negative in primary tissue was 13.6% (6/44); and negativication rate in metastatic lesions, being positive in primary tumor was 27.3% (12/44). The positivication rate of Her2 expression in metastatic lesions while being negative in primary tissue was 4.5% (2/44); and negativication rate while being positive in primary tumor was detected as 13.6% (6/44). When the hormone receptor status and Her2 expression of the patients followed-up are evaluated, receptor variation was detected in 23 of 44 patients. Conclusions: Our study confirms that biological properties of breast cancer may vary among primary tumors and asynchronised metastatic lesions. Further prospective studies are needed to better define the discordance of Her2 or HR status at primary tissue and metastatic sites.