The cancer-testis antigen NY-ESO-1 is highly expressed in myxoid and round cell subset of liposarcomas

Abstract

Liposarcomas are a heterogenous group of fat-derived sarcomas, and surgery with or without chemoradiation therapy remains the main stay of treatment. NY-ESO-1 is a cancer-testis antigen expressed in various cancers where it can induce both cellular and humoral immunity. Immunotherapy has shown promise in clinical trials involving NY-ESO-1-expressing tumors. Gene expression studies have shown upregulation of the gene for NY-ESO-1, CTAG1B, in myxoid and round cell liposarcomas. Herein, we evaluated the expression of NY-ESO-1 among liposarcoma subtypes by quantitative real-time PCR, western blot analysis, and immunohistochemistry. Frozen tissue for quantitative real-time PCR and western blot analysis was obtained for the following liposarcoma subtypes (n ¼ 15): myxoid and round cell (n ¼ 8); well-differentiated (n ¼ 4), and dedifferentiated (n ¼ 3). Formalin-fixed paraffin-embedded blocks were obtained for the following liposarcoma subtypes (n ¼ 44): myxoid and round cell (n ¼ 18); well-differentiated (n ¼ 10); dedifferentiated (n ¼ 10); and pleomorphic (n ¼ 6). Full sections were stained with monoclonal antibody NY-ESO-1, and staining was assessed for intensity (1 À 3 þ ), percentage of tumor positivity, and location. In all, 7/8 (88%) and 16/18 (89%) myxoid and round cell expressed CTAG1B and NY-ESO-1 by quantitative real-time PCR and immunohistochemistry, respectively. Western blot correlated with mRNA expression levels. By immunohistochemistry, 94% (15/16) of positive cases stained homogenously with 2 À 3 þ intensity. Also, 3/6 (50%) pleomorphic liposarcomas demonstrated a range of staining: 1 þ intensity in 50% of cells; 2 þ intensity in 5% of cells; and 3 þ intensity in 90% of cells. One case of dedifferentiated liposarcoma showed strong, diffuse staining (3 þ intensity in 75% of cells). Our study shows that both CTAG1B mRNA and protein are overexpressed with high frequency in myxoid and round cell liposarcoma, enabling the potential use of targeted immunotherapy in the treatment of this malignancy.

NY-ESO-1 is a sensitive and specific immunohistochemical marker for myxoid and round cell liposarcomas among related mesenchymal myxoid neoplasms

“…In our previous study, we reported that 7/8 (88%) and 16/18 (89%) myxoid and round cell liposarcomas expressed CTAG1B and NY-ESO-1 by quantitative real-time PCR and immunohistochemistry, respectively. 12 We also noted variable positive staining in a subset of pleomorphic liposarcomas (3/6) and an instance of strong, diffuse staining in dedifferentiated liposarcoma (1/10). Pollack et al 11 also reported NY-ESO-1 expression in 25/25 (100%) myxoid and round cell liposarcomas evaluated by immunohistochemistry and quantitative real-time PCR.…”

“…Both reports describe NY-ESO-1 expression as predominantly homogenous, which is notable given that cancer testis antigens usually demonstrate a heterogeneous staining pattern within a particular tumor. 5,11,12,26 In addition to possibly enabling an enhanced response to cancer testis antigen-directed immunotherapy, diffuse staining by NY-ESO-1 increases its appeal as an immunohistochemical marker of myxoid and round cell liposarcoma.…”

“…Of note, 18 cases of myxoid and round cell liposarcoma and 10 cases of well-differentiated liposarcoma were included from a previous study reporting NY-ESO-1 immunoreactivity. 12 Immunohistochemistry NY-ESO-1, clone E978 (Santa Cruz Biotechnology; Santa Cruz, CA, USA), was titered on normal testis, and testis was used as control tissue. Paraffinembedded tissue was cut at 4 microns, placed in a 60 1C oven for 1 h, cooled, and then deparaffinized and rehydrated through xylenes and graded ethanol solutions to water.…”

“…[7][8][9][10] Prompted by recent studies showing frequent expression of the cancer testis antigen NY-ESO-1 in myxoid and round cell liposarcoma, we sought to evaluate the utility of NY-ESO-1 as an immunohistochemical marker for this tumor type among mesenchymal myxoid neoplasms within the differential diagnosis, including extra-cardiac soft tissue myxomas, myxofibrosarcomas, low-grade fibromyxoid sarcomas, well-differentiated liposarcomas, lipomas, and extraskeletal myxoid chondrosarcoma. 11,12 …”

NY-ESO-1 (CTAG1B) expression in mesenchymal tumors

“…Recent studies have reported NY-ESO-1 expression in an especially large proportion of myxoid liposarcomas and synovial sarcomas. 2,[6][7][8][9] These studies also revealed the absence of NY-ESO-1 expression in their histologic mimics such as myxoma, myxofibrosarcoma, extraskeletal myxoid chondrosarcoma, and lowgrade fibromyxoid sarcoma, and concluded that immunohistochemical staining of NY-ESO-1 is useful not only for candidate selection in immunotherapy, but also for histologic differential diagnosis. A limitation of these previous studies is that the sample sizes were too small to be conclusive and lacked independent external validation.…”