BackgroundTo date, there are no effective therapeutic targeting agents for triple-negative breast cancer (TNBC), and PD-L1 has presented potential as an effective marker of immunotherapeutic agents. The aim of this study was to evaluate the expression of PD-L1 by three different immunohistochemical antibodies in TNBC.MethodsInterpretation of all three PD-L1 antibodies showed good concordance among three readers (kappa value >0.610) in both cancer cells and immune cells. Using a tissue microarray (TMA) constructed from 218 cases of TNBC, we performed immunohistochemical staining using three of the most popular commercially used PD-L1 monoclonal antibodies (clones 28-8, E1L3N and SP142) in cancer cells and immune cells.ResultsUsing various cut-off values of previous studies (1, 5, 10 and 50 %), the expression rates in cancer cells were: PD-L1 (E1L3N) (14.7, 14.7, 11.0, 2.3 %), PD-L1 (28-8) (13.3, 12.4, 10.1, 1.8 %), and PD-L1 (SP142) (11.5, 11.0, 6.9, 0.5 %), respectively. At the 5 % cut-off value, the discordance rate among the three antibodies was 6.0–10.6 % and was highest between PD-L1 (SP142) and the other two antibodies. The expression rates in immune cells were PD-L1 (E1L3N) (37.6 %), PD-L1 (28-8) (36.7 %), and PD-L1 (SP142) (19.3 %), and the discordance rate among the three antibodies ranged from 13.8 to 24.8 % and was also highest between PD-L1 (SP142) and the other two antibodies. Among stromal histologic types, higher PD-L1 expression in cancer cells and immune cells was measured in inflammatory-type (p < 0.05). The absence of PD-L1 (28-8) staining in immune cells was associated with shorter disease free survival (DFS) and overall survival (OS) (p = 0.043, and p = 0.021) in univariate analyses, and with shorter OS in multivariate Cox analysis (hazard ratio: 5.429, 95 % CI 1.214–24.28, p = 0.027).ConclusionsPD-L1 detection in cancer cells and immune cells varied by antibody clone. The greatest amount of staining occurred with PD-L1 (E1L3N), followed by PD-L1 (28-8) and PD-L1 (SP142). The concordance rate among monoclonal PD-L1 antibodies was higher between PD-L1 (28-8) and PD-L1 (E1L3N). To determine the gold standard antibody and the most appropriate cut-off value, further study of the clinical trial group treated with PD-L1 inhibitor is necessary.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-0925-6) contains supplementary material, which is available to authorized users.

Adipocytes are known to be involved in epithelial-mesenchymal transition (EMT) in several cancers. However, the role of adipocytes in the EMT of breast cancer cells is poorly understood. The purpose of this study was to investigate the involvement of adipocytes in the EMT in breast cancer. Breast cancer cell lines MCF-7, MDA-MB-453, MDA-MB-435S, MDA-MB-231, and MDA-MB-468 were co-cultured with adipocytes and analyzed for morphological changes, proliferation activity, EMT markers, migration, and invasion. In addition, 296 human breast cancer specimens were classified according to the presence of the fibrous or adipose stroma and analyzed by immunohistochemistry for the expression of estrogen and progesterone receptors, human epidermal growth factor receptor 2, antigen Ki-67, N-cadherin, Twist-related protein 1 (TWIST1), high-mobility group AT-hook 2, TGFβ, and S100 calcium-binding protein A4 using tissue microarray. After co-culture with adipocytes, MCF-7, MDA-MB-435S, and MDA-MB-231 cells exhibited elongated spindle-like morphology and increased proliferation; MDA-MB-435S and MDA-MB-231 cells also showed increased dispersion. In all tested breast cancer cells, adipocytes induced migration and invasion. The EMT-like phenotypic changes and increased cell migration and invasion were accompanied by the upregulation of matrix metallopeptidase 9 and TWIST1. Consistently, breast cancer tumors with the adipose stroma showed higher TWIST1 expression than those with the adipose stroma; however, no difference was observed in the levels of other EMT-related proteins. Adipocytes stimulate breast cancer cells to acquire aggressive tumor phenotype by inducing EMT-associated traits, and breast cancer with the adipose stroma expresses EMT markers as breast cancer with the fibrous stroma.

Strict LID for one week was sufficient to achieve target UIE values for RAIT preparation, even in iodine-rich areas.