Longitudinal Analysis and Prognostic Effect of Cancer-Testis Antigen Expression in Multiple Myeloma

Abstract

Purpose: Reliable data on the persistence of tumor expression of cancer-testis (CT) antigens over time and consequent analyses of the effect of CT antigen expression on the clinical course of malignancies are crucial for their evaluation as diagnostic markers and immunotherapeutic targets. Experimental Design: Applying conventional reverse transcription-PCR, real-time PCR, and Western blot, we did the first longitudinal study of CT antigen expression in multiple myeloma analyzing 330 bone marrow samples from 129 patients for the expression of four CT antigens (MAGE-C1/CT7, MAGE-C2/CT10, MAGE-A3, and SSX-2). Results: CT antigens were frequently and surprisingly persistently expressed, indicating that down-regulation of these immunogenic targets does not represent a common tumor escape mechanism in myeloma. We observed strong correlations of CT antigen expression levels with the clinical course of myeloma patients as indicated by the number of bone marrow^residing plasma cells and peripheral paraprotein levels, suggesting a role for CT antigens as independent tumor markers. Investigating the prognostic value of CT antigen expression in myeloma patients after allogeneic stem cell transplantation, we found that expression of genes, such as MAGE-C1, represents an important indicator of early relapse and dramatically reduced survival. Conclusions: Our findings suggest that CTantigens might promote the progression of multiple myeloma and especially MAGE-C1/CT7, which seems to play the role of a ''gatekeeper'' gene for other CT antigens, might characterize a more malignant phenotype. Importantly, our study also strongly supports the usefulness of CTantigens as diagnostic and prognostic markers as well as therapeutic targets in myeloma.Cancer-testis (CT) antigens are a diverse group of genes of which more than 40 families have been identified during the past 15 years (1). CT antigens have been considered promising targets for immunotherapy of human malignancies based on their tumor-restricted expression and on their immunogenicity in cancer patients. Both of these characteristics could render CT antigens important diagnostic and prognostic markers; however, thus far, this aspect of the biology of CT antigens has not intensively been explored.Although an impressive number of studies have shown expression of CT antigens in a large variety of human tumor types on the RNA as well as on the protein level (2), there has not been a single study analyzing the expression of CT antigens in a human cancer over time. This seems surprising because reliable data on the persistence of tumor-related CT antigen expression are a prerequisite for the evaluation of these tumorspecific proteins as diagnostic markers and immunotherapeutic targets, especially considering data suggesting that immunoselection might lead to down-regulation or loss of CT antigen expression in cancer patients (3,4).We have recently shown that CT antigens are commonly expressed and are capable of inducing antibody-mediated and T-cell -mediated immunity in m...

Cancer testis antigens in newly diagnosed and relapse multiple myeloma: prognostic markers and potential targets for immunotherapy

“…CTA expression in myeloma has been evaluated in large patient sets but emphasis has so far been on newly diagnosed patients. 13,16,29,30 Compared to the study of Condomines et al, 16 presence of gene expression frequency differed no more than 2-fold in 73% of overlapping genes when compared to the frequencies found in newly diagnosed patients in our study. Of these, 12 are highly correlated with a difference in frequency of no more than 1.5-fold, including MAGEC1, MAGEA5 and SSX3; 61%, 26% and 3% in our study and 66%, 22% and 3% in the study of Condomines et al 16 In some cases, different probe sets belonging to the same gene may explain the difference in expression frequencies between the two studies.…”

“…Atanackovic et al reported on the longitudinal analysis of 4 CTA genes in 17 patients during treatment, and in most cases the expression of these genes persisted from initial presentation to relapse. 13 Only MAGEC2 demonstrated a clear reduction in terms of foldchange in our study and is also the gene which was most frequently decreased in the study of Atanackovic et al 13 The relationship between CTA expression and its prognostic value is underlined by the expression of SSX1 mentioned above. Moreover, multivariate analysis identifies SSX1 as an independent prognostic factor associated with poor overall survival in relapse cases, with CTAG2 prognostic for progression free survival in this set.…”

“…Although 2 out of 3 of the top CTA genes with testis restricted expression demonstrate significantly reduced frequency of expression in relapse cases, the proportion of samples expressing one of the top 3 genes in relapse cases is still 71%, which compares favorably to the 83% in newly diagnosed cases. In a study by Atanackovic et al, 13 the frequency of MAGEC1, MAGEA3, MAGEC2 and SSX2 expression was determined in a set of myeloma cases: 65%, 52%, 43% and 12%, respectively. The expression presence in our study was lower for most of these genes; 71%, 38%, 29% and 7%, respectively.…”

“…Expression of MAGEC1 by Q-PCR has also been reported to correlate with disease burden following therapy. 13 A small series of 10 cytospins derived from purified CD138-positive tumor cells was stained for MAGEC1 by immunohistochemistry (IHC) (Online Supplementary Figure S3); a clear correlation was observed for gene presence call and protein expression. In fact, MAGEC1 presence calls were found only in cases with more than 50% of the tumor cells positive for MAGEC1 by IHC.…”

“…CTA expression after treatment has been shown for a limited number of CTAs, including PASD1, CTAG1B and MAGEC1/CT7. [11][12][13][14][15] In addition, in MM, expression of CTA genes has been shown to be strongly correlated to clinical outcome, i.e. presence of CTA expression has been linked to shorter survival.…”