Cancer/Testis Antigens MAGE-C1/CT7 and MAGE-C2/CT10 Are Expressed in 90% of Multiple Myeloma Samples and Can Be Explored in Combined Immunotherapy for This Malignancy
Authors: de Carvalho Fabricio , Lia Veruska , Alves Fook , Moisés Walter , Braga Tobias , Xavier Celso Vieira , Colleoni Gisele Wally Braga 
Published: October 2019

Abstract
Abstract 4974

Background:
Multiple Myeloma (MM) is a malignant proliferation of B-cells with plasma cell differentiation. Vaccines formulated with antigens associated with myeloma cells can instruct the immune system to eliminate malignant cells. Can/Testis Antigens (CTAs) tumor-associated antigens are identified in several human malignant neoplasms and in normal testis, fetal ovary and trophoblast cells. MAGE CTA genes are recognized by CTL (cytotoxic T cell) and are strictly tumor-specific. MAGE-C1/CT7 and MAGE-C2/CT10 are highly immunogenic and both CTAs have been previously shown in various human tumors, suggesting its potential role to evoke both humoral and cellular immune responses.

Objective:
We evaluated MAGE-C1/CT7 and MAGE-C2/CT10 expression in bone marrow (BM) aspirates collected from patients with MM, solitary plasmacytomas, MGUS (monoclonal gammopathy of undetermined significance) and normal controls to evaluate potential combination of CTA genes for immunotherapy in this disease by RT-PCR (reverse transcription-polymerase chain reaction).

Material and Methods:
BM aspirates from 20 MM patients [30% ISS (International Staging System) stage 1–2 and 70% stage 3], five solitary plasmacytomas, four MGUS and five normal BM aspirates. RNA was prepared from total BM aspirates using TRIzol, followed by synthesis of cDNA with SuperScript III, according to the manufacturer's instructions. MAGE-C1/CT7 and MAGE-C2/CT10 were analyzed by RT-PCR and 2% agarose gel electrophoresis and visualized by Sybr Safe.

Results:
MAGE-C1/CT7 was positive in 75% (15/20) and MAGE-C2/CT-10 in 70% (14/20) of MM cases. In 11 out of 20 MM cases (55%), both CTAs were positive and in 18 out of 20 samples (90%) the expression of at least one of the genes could be detected by RT-PCR. In the other monoclonal gammopathies (solitary plasmacytomas and MGUS), MAGE-C1/CT7 and MAGE-C2/CT10 were expressed in at least one of the analyzed cases. All BM aspirates collected from healthy donors were negative for both CTAs evaluated, showing restricted expression of these genes in monoclonal gammopathies. Considering the International Staging System (ISS), the data show that expression of both CTA genes were widely expressed in MM samples studied, independently on the stage of disease.

Conclusions:
These findings suggest that both MAGE-C1/CT7 and MAGE-C2/C10 CTA genes can have a biological role in MM distinct clinical phases and maybe contribute to malignant plasma cell development. The high frequency found in MM patients suggests that the subfamily of MAGE-C has a role on the development of myeloma. Although the function of these genes is still poorly understood, several studies have shown that MAGE-C1/CT7 and MAGE-C2/CT10 genes are able to elicit spontaneous immune responses; therefore they can be considered potential targets for cell therapy in this incurable disease.

Disclosures:
No relevant conflicts of interest to declare.