Abstract 1084: The role of tumor-associated neutrophils (TAN) and CD8 positive T lymphocyte in the progression of hepatocellular carcinoma (HCC)

Abstract [Background]Neutrophils are known as immune cells involved in biological defense against foreign substances. On the other hand, in the tumor microenvironment, it is said that neutrophils affect on tumor progression as a tumor-associated neutrophil (TAN). Although, TAN and other immune cells in the progression of HCC is unclear. [Method]One hundred twenty eight patients who underwent curative hepatectomy for HCC in our institution were enrolled. Immunohistochemistry was performed with CD66b and CD8 antibody to evaluate TAN and CD8+ T lymphocytes, respectively. Expression high or low was determined by cut-off value of each number of immune cells. We counted the number of each immune cells in both tumor (intra-tumor) and the tumor marginal area (extra-tumor). The relationship between the infiltration of each immune cell and clinicopathological factors was examined. [Result]Comparing the number of immune cells of intra-tumor and extra-tumor, there were significantly more cells in extra-tumor area (p<0.001). There was no difference in between background clinicopathological factors and the number of TAN or CD8+ T lymphocytes in either intra-tumor or extra-tumor areas. Overall survival was significantly better in the group with high CD8+ T lymphocytes in extra-tumor area compared to the low group (p = 0.0491), intriguingly though CD8+ T lymphocytes in intra-tumor area was not associated with prognosis. In the contrast, overall survival was significantly poor in the group with high TAN in extra-tumor area compared to the low group (p = 0.0296), though TAN in intra-tumor area was not associated with prognosis. [Conclusion]Infiltration of TAN and CD8+ T lymphocytes not in intra-tumor but in the extra-tumor area may be involved in the progression of HCC. Citation Format: Toshihiko Yusa, Hirohisa Okabe, Yo-ichi Yamashita, Takanobu Yamao, Naoki Umezaki, Tatsunori Miyata, Shigeki Nakagawa, Hiromitsu Hayashi, Katsunori Imai, Akira Chikamoto, Takatoshi Ishiko, Hideo Baba. The role of tumor-associated neutrophils (TAN) and CD8 positive T lymphocyte in the progression of hepatocellular carcinoma (HCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1084.