Moreover, vimentin is selectively expressed in aggressive learn more breast cancer cell lines [3]. Elevated vimentin expression level correlates well with up-regulated migration and invasion of cancer cells [3, 4]. The transfection of the non-invasive human breast cancer cell line (MCF7) with vimentin gene led to accelerated invasiveness [5]. Other data showed that more invasive breast cancer lines expressed vimentin, suggesting its usefulness in identifying cases with poorer prognosis [6]. Vimentin reactive cells in benign and malignant breast tissue have been described by many

authors [4, 7]. The same applies to a possible association with clinically aggressive behavior of tumours [7], which may be explained by VEGFR inhibitor correlation with estrogen receptor negativity [8, 9], high Ki-67 level [9] and poor differentiation of tumours (high grade) [10, 11]. Few reports are in opposite, as they showed that vimentin expression did not inversely predict patient survival [12]. The cDNA microrray experiments enabled the identification of different subgroups of breast tumours with distinct molecular signatures [13–15]. This molecular classification delineated at least four biologically different phenotypes:

luminal phenotype (generally, estrogen receptor positive tumours), normal breast-like phenotype and estrogen receptor negative tumours, comprising the subgroups of HER2 (overexpression of ERBB2 oncogene) and basal-like phenotypes (tumours expressing genetic markers that are characteristic of the myoepithelium of the normal mammary gland, such as epidermal growth GF120918 order factor receptor, p63 and basal cytokeratins CK 5/6,

CK 14, CK17 [13–15]. It is also known that a subgroup with HER 2 overexpression and basal-like phenotype correlate with poor prognosis. Many efforts have been undertaken to reproduce this classification Fenbendazole with the use of immunohistochemistry instead of assessment of mRNA [16–18]. Some researchers suggested that immunohistochemically triple negative tumours (ER, PgR, and HER 2-negativity) could reliably be defined as basal-like tumours, making these two subgroups synonymous [19]. Others believe that equating triple negative tumours with basal-like breast cancer is misleading [20]. However, there is a common agreement that the key point of basal-like characteristics is triple negativity of tumours. On the other hand, it should be stressed that not only basal-like cancers harbour a triple negative phenotype at the mRNA level, and normal-breast like cancers also have this feature [13, 21]. It has been shown that typical features of basal-like tumours include the expression of: high molecular weight cytokeratins – CK5/6, 14, 17 (so-called basal type cytokeratins) [18, 22, 23], expression of epidermal growth factor receptor (EGFR), c-kit, P53, and vimentin [4, 16, 18, 20, 23, 24].