Expression of MAGE-A antigens is frequent in triple-negative breast cancers but does not correlate with that of basal-like markers

Prognostic Value of "Basal-like" Morphology, Tumor-Infiltrating Lymphocytes and Multi-MAGE-A Expression in Triple-Negative Breast Cancer

"Basal-like" (BL) morphology and the expression of cancer testis antigens (CTA) in breast cancer still have unclear prognostic significance. The aim of our research was to explore correlations of the morphological characteristics and tumor microenvironment in triple-negative breast carcinomas (TNBCs) with multi-MAGE-A CTA expression and to determine their prognostic significance. Clinical records of breast cancer patients who underwent surgery between January 2017 and December 2018 in four major Croatian clinical centers were analyzed. A total of 97 non-metastatic TNBCs with available tissue samples and treatment information were identified. Cancer tissue sections were additionally stained with programmed death-ligand 1 (PD-L1) Ventana (SP142) and multi-MAGE-A (mAb 57B). BL morphology was detected in 47 (49%) TNBCs and was associated with a higher Ki-67 proliferation index and histologic grade. Expression of multi-MAGE-A was observed in 77 (79%) TNBCs and was significantly associated with BL morphology. Lymphocyte-predominant breast cancer (LPBC) status was detected in 11 cases (11.3%) and significantly correlated with the Ki-67 proliferation index, increased number of intratumoral lymphocytes (itTIL), and PD-L1 expression. No impact of BL morphology, multi-MAGE-A expression, histologic type, or LPBC status on disease-free survival was observed. Our data suggest that tumor morphology could help identify patients with potential benefits from CTA-targeting immunotherapy.

Cancer-Testis Antigens in Triple-Negative Breast Cancer: Role and Potential Utility in Clinical Practice

Breast cancer cells commonly express tumour-associated antigens that can induce immune responses to eradicate the tumour. Triple-negative breast cancer (TNBC) is a form of breast cancer lacking the expression of hormone receptors and cerbB2 (HER2) and tends to be more aggressive and associated with poorer prognoses due to the limited treatment options. Characterisation of biomarkers or treatment targets is thus of great significance in revealing additional therapeutic options. Cancer-testis antigens (CTAs) are tumour-associated antigens that have garnered strong attention as potential clinical biomarkers in targeted immunotherapy due to their cancer-restricted expressions and robust immunogenicity. Previous clinical studies reported that CTAs correlated with negative hormonal status, advanced tumour behaviour and a poor prognosis in a variety of cancers. Various studies also demonstrated the oncogenic potential of CTAs in cell proliferation by inhibiting cell death and inducing metastasis. Multiple clinical trials are in progress to evaluate the role of CTAs as treatment targets in various cancers. CTAs hold great promise as potential treatment targets and biomarkers in cancer, and further research could be conducted on elucidating the mechanism of actions of CTAs in breast cancer or combination therapy with other immune modulators. In the current review, we summarise the current understandings of CTAs in TNBC, addressing the role and utility of CTAs in TNBC, as well as discussing the potential applications and advantage of incorporating CTAs in clinical practise.

Upregulation of RHOXF2 and ODF4 Expression in Breast Cancer Tissues

Objective

During the past decade, the importance of biomarker discovery has been highlighted in many aspects of cancer research. Biomarkers may have a role in early detection of cancer, prognosis and survival evaluation as well as drug response. Cancer-testis antigens (CTAs) have gained attention as cancer biomarkers because of their expression in a wide variety of tumors and restricted expression in testis. The aim of this study was to find putative biomarkers for breast cancer.

Materials and Methods

In this applied-descriptive study, the expression of 4 CTAs, namely acrosin binding protein (ACRBP), outer dense fiber 4 (ODF4), Rhox homeobox family member 2 (RHOXF2) and spermatogenesis associated 19 (SPATA19) were ana- lyzed at the transcript level in two breast cancer lines (MCF-7 and MDA-MB-231), 40 invasive ductal carcinoma samples and their adjacent normal tissues as well as 10 fibroadenoma samples by means of quantitative real-time reverse transcription polymerase chain reaction (RT-PCR).

Results

All four genes were expressed in both cell lines. Expression of ODF4 and RH- OXF2 was detected in 62.5% and 60% of breast cancer tissues but in 22.5 and 17.5% of normal tissues examined respectively. The expression of both RHOXF2 and ODF4 was upregulated in cancerous tissues compared with their normal adjacent tissues by 3.31 and 2.96-fold respectively. The expression of both genes was correlated with HER2/neu overexpression. RHOXF2 expression but not ODF4 was correlated with higher stages of tumors. However, no significant association was seen between expression patterns and estrogen and progesterone receptors status.

Conclusion

ODF4 and RHOXF2 are proposed as putative breast cancer biomarkers at the transcript level. However, their expression at protein level should be evaluated in future studies.

Overexpression of MAGE-A9 predicts unfavorable outcome in breast cancer

Melanoma-associated antigens (MAGEs) are a group of well-characterized members of the cancer/testis antigen (CTA) family, which is one of the largest groups of human tumor-associated antigens. MAGE-A9 is a particular member in the context of the MAGE-A gene family and was defined as presenting prognostic relevance in certain type of human cancer. However, the expression of MAGE-A9 in invasive ductal breast cancer (IDC) and the relationship with the clinical attributes of IDC, especially prognostic characteristic, remain poorly understood. In this present study, one-step quantitative reverse transcription polymerase chain reaction (18 fresh-frozen IDC tissues and corresponding non-cancerous tissues) and immunohistochemistry by tissue microarrays (82 IDC tissue samples and 70 matched tumor-adjacent non-cancerous tissue samples) were performed to characterize expression of the MAGE-A9 gene in IDC. Kaplan-Meier survival and Cox regression analyses were performed to evaluate the prognosis of IDC. The results of qPCR and IHC analysis showed that the expression of MAGE-A9 in IDC was significantly higher than that in corresponding non-cancerous tissue. Moreover, the expression level of MAGE-A9 protein in IDC was significantly related to histological grade (p = 0.011) and distant metastasis (p = 0.019). Multivariate analysis with the Cox regression model showed that MAGE-A9 protein expression (p = 0.009), histological grade (p = 0.014), lymph node metastasis (p = 0.012) and distant metastasis (p = 0.011) were independent prognostic factors for overall survival of IDC patients. The data suggest that MAGE-A9 expression is correlated with malignant attributes of IDC and it may serve as a novel prognostic factor and an ideal candidate for targeted therapy in IDC treatment.

High expression of MAGE-A9 correlates with unfavorable survival in hepatocellular carcinoma

Melanoma-associated antigens (MAGE)-A9 has been reported to play important roles in the development of human cancers. However, the association between MAGE-A9 expression and the clinicopathological characteristics of hepatocellular carcinoma (HCC) is not well understood. The study was to detect the expression of MAGE-A9 in human HCC and investigate the association between its expression and the clinicopathological characteristics of HCC. Reverse transcription-polymerase chain reaction (RT-PCR), one-step quantitative -PCR (qPCR) and immunohistochemistry (IHC) analyses were performed to characterize the expression of MAGE-A9 in HCC cell lines and tissues. Kaplan-Meier survival and Cox regression analyses were employed to evaluate the prognosis of 100 HCC patients. The results showed that the expression of MAGE-A9 in HCC was significantly higher than that in non-cancerous cells and tissues. Moreover, the expression level of the MAGE-A9 protein in HCC was related to the pathological grade (p = 0.003), portal vein invasion (p = 0.001), distant metastasis (p = 0.022) and TNM stage (p = 0.005). Cox regression analysis further revealed that MAGE-A9 expression is an independent prognostic factor for disease-free survival (p = 0.006) and overall survival (p = 0.022). These data are the first to indicate that MAGE-A9 expression is a valuable prognostic biomarker for HCC and that high MAGE-A9 expression suggests unfavorable survival outcomes in HCC patients.

Emerging immunotherapy strategies in breast cancer

Although immunogenicity is typically associated with renal cell carcinomas and melanoma, there are several compelling reasons why immune-based therapies should be explored in breast cancer. First, breast cancers express multiple putative tumor-associated antigens, such as HER-2 and MUC-1, which have been the successful focus of vaccine development over the past decade, translating into tumor-specific immune responses and, in some cases, clinical benefit. Second, passive immune strategies with anti-HER-2 antibodies, such as trastuzumab and pertuzumab, have led to survival benefits in breast cancer. Finally, the successes observed with novel immunotherapeutic strategies, such as immune checkpoint blockade and adoptive T-cell therapies in other malignancies, combined with a growing body of literature that supports an interplay between solid tumors and the immune system, indicate that these strategies have the potential to revolutionize the treatment of breast cancer.

Cancer-testis genes as candidates for immunotherapy in breast cancer

Cancer-testis (CT) antigens are tumor-associated antigens attracting immunologists for their possible application in the immunotherapy of cancer. Several clinical trials have assessed their therapeutic potentials in cancer patients. Breast cancers, especially triple-negative cancers are among those with significant expression of CT genes. Identification of CT genes with high expression in cancer patients is the prerequisite for any immunotherapeutic approach. CT genes have gained attention not only for immunotherapy of cancer patients, but also for immunoprevention in high-risk individuals. Many CT genes have proved to be immunogenic in breast cancer patients suggesting the basis for the development of polyvalent vaccines.