This study was to re-examine the usefulness of biomarker assays in all multiple tumors in the same breast, and to evaluate the genetic heterogeneity of unilateral multiple breast carcinoma.
All of the cases met the criteria for synchronous multicentric breast carcinomas. Tumors were either 5 cm apart or within the different breast quadrants, with no identifiable connection between lesions, and were diagnosed at the same time for an individual patient.
In the present study, 32 tumors from 15 patients with synchronous unilateral breast cancer were immunostained for estrogen receptor (ER), progesterone receptor (PR), and HER-2, and also underwent microsatellite analysis using 10 polymorphic markers. The ER and PR expression profile was similar in all tumors from the same patient. Discordant HER-2 immunoreactivity was found and confirmed by HER-2 FISH test in one case, and heterogeneity in the microsatellite pattern was observed in 6 patients.
With the routinely-used biomarkers (ER, PR, and HER-2), heterogeneity was minimal, however, with more frequent differences noted at the genetic levels.
breast cancer, unilateral multiple breast cancer, microsatellite, loss of heterozygosity, HER-2