Abstract 726: Correlation between T cell infiltration subtypes and intratumoral hormone levels in endometrial cancer

Abstract

Abstract T cells in the tumor microenvironment, or tumor-infiltrating lymphocytes (TILs), have been recognized to play a critical role in tumor immunity. TILs are heterogeneously defined, and different T cell subsets have various effects. The properties of some T cell markers, such as CD3, CD4, CD8, and forkhead box P3 (FOXP3), are poor prognostic factors in several types of cancers. The effects of sex steroid hormones on T cell function in inflammation are known, and estrogen and androgen regulate the secretion of cytokines to enhance and attenuate, respectively, the immune response. While intratumoral estrogen and androgen synthesis plays an important role in the progression of cancer cells in hormone-dependent cancers, the relationship between intratumoral hormone levels and TIL subtypes is unclear. In this study, we examined the correlation between intratumoral hormone concentrations and expression scores of TIL markers in endometrial cancer. We employed frozen and formalin-fixed paraffin-embedded (FFPE) tissues of 19 endometrial cancer tissues (G1, n=6; G2, n=5; G3, n=6; Serous, n=2). Hormone concentrations were measured by LC-MC/MS from the frozen sample, and immunohistochemistry of T cell markers was performed using FFPE tissues. The five T cell markers examined in this study were CD3 (total T cells), CD4 (helper T cells), CD8 (cytotoxic T cells), FOXP3 (regulatory T cells), and thymocyte selection-associated HMG box (TOX) (exhausted T cells). The number of intratumoral CD3 in an arbitrary two-field (magnification, ×200) was counted and used as the CD3 score. Similarly, the number of other markers was counted, and the ratio to CD3 was used as the score for each marker. A correlation was found between TOX and CD8 using correlation between markers. The median scores for CD3 and CD8 were significantly higher in type 1 (G1 and G2) than in type 2 (G3 and serous) (CD3, p=0.031; CD8, P=0.031). The CD4 score had a positive correlation with estrogen (estrone, r2=0.591; estradiol, r2=0.501) and androgen (dihydrotestosterone, r2=0.327) concentrations. There was a poor negative correlation between cortisol concentration and CD8 score (r2=0.203). Estrogen and androgen at the tumor in situ were considered to affect TILs, especially CD4 positive T cells. It is also suggested that cortisol acts on immunosuppression, even locally in the tumor. This study showed the potential of a combination of immunotherapy and hormone therapy in endometrial cancer. Citation Format: Yasuhiro Miki, Fuka Onuma, Kiyoshi Takagi, Erina Iwabuchi, Takashi Suzuki, Hironobu Sasano, Kiyoshi Ito. Correlation between T cell infiltration subtypes and intratumoral hormone levels in endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 726.