Immunohistochemical characteristics of breast cancer in Kazakh and Russian populations

N. V. Malyshev, Vladimir Kulishov, V. S. Perminov, Valentina Sirota

2009

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DOI 10.1200/jco.2009.27.15_suppl.e22162
Data confidence 70 medium
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Abstract

e22162 Background: Ethnic differences of breast cancer were satisfactory investigated in different populations of the United States and some important findings were revealed. In other areas of the world amount of similar studies is relatively low. Our aim was to investigate the ethnical differences in the expression of standard immunohistochemical markers of breast cancer between two main nations of Kazakhstan and to reveal possible correlations between these markers and prognosis of the patients. Methods: 664 breast cancer patients, treated in Karaganda Regional Cancer Center during 2006–2007, were included in this study (222 patients of Kazakh population and 442 patients of Russian population). Immunohistochemical expression of estrogen and progesterone receptors (ER and PR) and Her2/neu was determined in all patients. Expression of steroid receptors was counted as positive if staining was presented in more than one percent of breast cancer cells. Her2/neu expression was divided in two groups: 0, 1+ - negative expression, 2+, 3+ - positive expression. The obtained data was calculated and processed by statistical program - Statistica 6.0. Results: Breast cancer in Kazakh patients demonstrated higher level of Her2/neu positive expression (31.5% versus 23.8, p<0.05) and lower level of isolated ER and PR expression (36.5 versus 44.3, p=0.05). Still, breast cancer in Russian patients was more frequently associated with basal phenotype (15.2 versus 9.5, p<0.05).Strong inverse correlation was observed between age of patients and Her2/neu status (p=0.0005) and direct correlation between age and positive expression of steroid receptors (p<0.05). These correlations were observed in both populations. Conclusions: Breast cancer in Kazakh population was statistically significantly associated with unfavorable prognostic and predictive immunohistochemical status, such as higher expression of Her2/neu and lower expression of steroid receptors. Nevertheless elder patients were more likely to have less aggressive disease, independently from population. No significant financial relationships to disclose.