Abstract 5409: Cancer immunosuppression: The role of human leukocyte antigen G expression

Abstract

Abstract Human leukocyte antigen G (HLA-G) is an immunotolerant nonclassical major histocompatibility complex class Ib molecule. During pregnancy it is expressed by trophoblastic placental cells to protect the fetus from maternal alloreactivity. HLA-G is involved in cancer immune evasion and is overexpressed by many tumors. Reverse transcription-polymerase chain reaction and immunohistochemistry were used to examine HLA-G expression in human normal breast and breast cancer cell lines, and human normal breast and breast cancer tissues. Reverse transcription-polymerase chain reaction confirmed that normal epithelial MCF-12A cells had no HLA-G mRNA, but cancer cell lines MCF-7, T47D, and MDA-MB-231 and NCI/Adr-Res had various levels of HLA-G mRNA expression. Thirty-eight breast cancers and 12 normal breast tissues were examined by immunohistochemistry. Fifty-eight percent (22/38) of cancers had medium to strong staining for HLA-G, whereas only 8% (1/12) of normal breast tissues had medium to strong staining, and the difference was statistically significant (p<0.05). HLA-G staining was found in the cytoplasm and membranes of cancer cells. In conclusion breast cancer cells overexpress HLA-G mRNA and protein, which probably contributes to immune evasion and treatment resistance. We believe HLA-G should be monitored in breast and other epithelial cancers as it may be both a prognostic indicator and a therapeutic target. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5409. doi:1538-7445.AM2012-5409