Expression and Clinical Significance of Herpes Virus Entry Mediator (HVEM) in Breast Cancer.

BACKGROUND: Immune checkpoint blockades are currently actively investigated in invasive breast cancers. Given the complexity of immune regulation, multiple inhibitory molecules within the immune checkpoint framework would be involved in tumor immune escape. Evaluation of the components within the framework is a prerequisite for not only identification of additional treatment targets and optimization of immunotherapeutic strategies but also understanding the prognostic value of these molecules. METHODS AND RESULTS: We examined a recently described component, herpes virus entry mediator (HVEM), in a large cohort of invasive breast cancers using immunohistochemistry, and evaluated its clinical relevance. HVEM expression was associated with aggressive tumor features, namely high grade (p < 0.001), high pT (p = 0.001) and pN stage (p = 0.008), and was most prevalently found in human epidermal growth factor receptor 2-overexpressed subtype (67%). Interestingly, a negative association with programmed death-ligand 1 (p = 0.021) has been observed. The prognostic impact of HVEM depended on the level of tumor-infiltrating lymphocytes (TILs), with the worst outcome occurring in patients with low TIL, HVEM-positive tumors. CONCLUSION: HVEM plays significant oncogenic roles in breast carcinogenesis, and may also be a tumor-specific target.

Expression and clinical significance of carcinoembryonic antigen-related cell adhesion molecule 6 in breast cancers.

Carcino-embryonic antigen-related cell adhesion molecule 6 (CEACAM6), one of the members of human carcino-embryonic antigens, is a multifunctional regulatory protein involved in various cellular processes in cancers. Its role in malignant transformation and the clinical significance has been extensively studied in colonic and pancreatic cancers. However, relatively few studies have been done on breast cancers. In the current study, CEACAM6 expression in two independent cohorts of invasive breast cancers were evaluated immunohistochemically and correlated with clinico-pathological features, biomarker profiles and patient survival. In the primary cohort, CEACAM6 expression was detected in 37.1 % (312/840) of primary invasive cancers. It was positively correlated with HER2 (p < 0.001). Concordantly, HER2-OE subtype showed the highest CEACAM6 expression (62.7 %) among all molecular subtypes; whereas, other subtypes also showed substantial CEACAM6 expression (21.8-37.5 %). Interestingly, a significantly worse overall survival was found in high pN stage HER2 positive cancers with CEACAM6 positivity (log-rank = 4.452, p = 0.035) and this could be validated in an independent cohort. Additionally, HER2 signaling was found to induce SMAD3 phosphorylation and CEACAM6 expression in a cell line model. Likewise, in the primary tumors, a positive association was found between HER2 and SMAD3 phosphorylation in CEACAM6 positive cancers (p = 0.012). Overall, CEACAM6 was widely expressed in different molecular subtypes, but highest and significantly in HER2-OE breast cancer. Within this group, CEACAM6 was associated with adverse high nodal stage patient outcome. Given the wide expression of CEACAM6 in all breast cancers, its roles as prognostic marker and therapeutic target warrant further evaluation.

CX3CL1 expression is associated with poor outcome in breast cancer patients.

The significance of chemokines in cancer biology has been widely recognized in recent years. CX3CL1 is a unique subclass of chemokine with complex functions, including recruitment of anti-tumor leukocytes and promoting cancer survival, thus affecting cancer progression in both the directions. It is not clear how these different functions interact in breast cancers. This is further complicated by the heterogeneity of breast cancer, and differential association of CX3CL1 with different subgroups could be present. There is only limited knowledge of CX3CL1 expression profile, its relationship with different biological features, subtypes, and outcomes in breast cancers. In this study, CX3CL1 expression was examined in a large cohort of breast cancers by immunohistochemistry and its association with clinicopathological factors, biomarker expression, and impact on patients' survival was assessed. High CX3CL1 expression was detected in 33.3 % (252/757) of primary invasive cancers. In line with its chemo-attractant function, CX3CL1 expression correlated positively with increased tumor infiltrating lymphocytes (TIL) (p = 0.005). In addition, CX3CL1 also correlated positively with adverse features in breast cancers, including lymph node involvement (p = 0.007), high Ki67 (p = 0.002), α-B crystallin expression (p = 0.008), and luminal B (worse prognosis luminal cancers) subtype (p = 0.024). Consistently, breast cancers with high expression of CX3CL1 were found to have a poorer overall survival (χ(2) = 4.797, p = 0.029). Interestingly, the adverse effect of CX3CL1 on outcome appeared to be more prominent in cancers with low TIL. These findings indicated that CX3CL1 could also have a pro-tumor role in breast cancer, despite its previously suggested role in enhancing anti-tumor immunity. The results highlighted the complicated functions of CX3CL1 in breast carcinogenesis. Further studies are needed to clarify the relative contribution of these anti- and pro-tumor functions in order to understand the true prognostic and potential therapeutic values of CX3CL1.

P-cadherin and vimentin are useful basal markers in breast cancers.

Basal-like breast cancer (BLBC) is the breast cancer subtype defined by gene profiling and generates keen clinical interest. Immunohistochemical panels using basal cytokeratins and epidermal growth factor receptor are widely adopted for its identification. Nonetheless, there are concerns about the risk for missing some true BLBCs. Both P-cadherin and vimentin have been proposed as BLBC markers, but their usefulness for BLBC classification has not been well documented. In this study, we evaluated by immunohistochemistry their expression in a large cohort of breast carcinoma. Cancers expressing vimentin or P-cadherin showed BLBC-related morphological features (high grade, presence of necrosis, and lymphocytic infiltration; P < .001 for all except P = .006 for vimentin with lymphocytic infiltration) and immunohistochemical profile (P < .001 for all markers tested except P = .007 for vimentin with human epidermal growth factor receptor 2). Concordantly, they were significantly associated with BLBC (P < .001 for both). Nonetheless, they did not appear to be good stand-alone BLBC markers. Compared with the commonly used reference panel, the specificity (95.9%) and sensitivity (43.1%) of coexpression of vimentin and P-cadherin were better than most single markers or their combinations tested. Moreover, their coexpression was significantly associated with basal features in non-BLBCs and worse disease-free survival in triple-negative breast cancers (hazard ratio, 2.232; P = .027). This raised the possibility that the vimentin and P-cadherin combination can be used to identify BLBC especially those that were missed by the commonly used basal cytokeratins and epidermal growth factor receptor panel. Together, P-cadherin and vimentin could be adjunctive to the commonly used immunohistochemical surrogates for BLBC identification.