Tumor infiltrating CD8⁺T lymphocyte count is independent of tumor TLR9 status in treatment naïve triple negative breast cancer and renal cell carcinoma

Abstract

Toll-like receptor 9 (TLR9) is a cellular DNA-receptor of the innate immune system that is widely expressed in cancers. We demonstrated that low tumor TLR9 expression predicts poor disease-specific survival in triple negative breast cancer (TNBC) and renal cell carcinoma (RCC). We hypothesized that this is because TLR9 expression affects tumor immunophenotype. To begin to test this, we compared the number of tumor infiltrating CD8 C T lymphocytes with TLR9 expression in treatment na€ ıve breast cancer (n D 197) and RCC (n D 94) cohorts with known TLR9 expression status. CD8 C T lymphocyte counts were assayed with image analysis after immunohistochemistry (IHC). Tumor TLR9 expression was not correlated with CD8C T cell counts in breast cancer or RCC. CD8 C T cell counts were significantly associated with tumor proliferation index in TNBC, but not in non-TNBC. CD8C T cell counts were also significantly associated with tumor grade in non-TNBC, but not in TNBC. In RCC, CD8C T cell counts were significantly associated with tumor stage. CD8 C T cell counts were significantly associated with prognosis in TNBC and RCC, but the presence of CD8 C T cells in these tumors had opposite effects on disease-specific survival: High CD8 C counts were associated with better prognosis in TNBC and worse prognosis in RCC. Among TNBC patients, those with low tumor TLR9 and low CD8 C T cell counts had the poorest prognosis (log-rank p D 0.0002 vs. high tumor TLR9 and high CD8 C T cell count). In conclusion, pre-treatment tumor TLR9 status is not associated with tumor infiltrating CD8 C T lymphocytes in TNBC or RCC. The combination of TLR9 and CD8 C TIL count might be a novel composite prognostic marker in TNBC.

Suppression of Type I IFN Signaling in Tumors Mediates Resistance to Anti-PD-1 Treatment That Can Be Overcome by Radiotherapy

“…Thus, when levels of MHC class I and II expression are low, fewer T cells and IFNγ-producing antitumor T cells are present in the resistant tumors. Clinical studies of anti-PD-1 nonresponding tumors have shown reduced numbers of TILs in these tumors (7), findings similar to what we observed in the anti-PD-1 resistant tumor model (Fig. 6E).…”

“…Because clinical studies have suggested that PD-L1 expression on tumor tissues correlates with objective response to anti-PD-1 therapy (5–7), we next studied the expression of PD-L1 on the parental and resistant tumor cells. The cell lines from in vitro culture showed similar PD-L1 expression levels (Supplementary Fig.…”

“…Antitumor responses are associated with the numbers and phenotypes of immune cells that infiltrate into tumors (14);having abundant TILs at diagnosis is associated with better prognosis (5,7,14). To understand antitumor immune profiling between the parental and resistant tumors, we isolated tumor-associated immune cells for flow cytometry analysis.…”

“…Nevertheless, large proportions of patients do not respond to anti-PD-1/PD-L1 immunotherapies. Some clinical studies have suggested that PD-L1 expression on tumor tissues correlates with objective response to the anti-PD-1 therapy (5–7), but response rates among patients with PD-L1-positive tumors are less than 50% in most studies (6,7), and some patients with tumors that express little or no PD-L1 still show some response to anti-PD-1/anti-PD-L1 therapy (6,7). This suggests that PD-L1 expression is not the sole mechanism that determines if tumors respond to anti-PD-1/PD-L1 treatment.…”

Biopathological Significance of TLR9 Expression in Cancer Cells and Tumor Microenvironment Across Invasive Breast Carcinomas Subtypes

“…Interestingly, TNCs with TLR9 overexpression were significantly correlated with development of a fibrous (P = 1.2×10 −6 ) and inflammatory microenvironment (P < 10 −7 ) with accumulation of CAFs and MICs overexpressing TLR9 and numerous CD4 lymphocytes, Treg lymphocytes and CD8 CD45RO memory cells (P = 0.016). Moreover, high contents of stromal inflammation, CAFs and MICs overexpressing TLR9 and numerous cytotoxic CD8 lymphocytes were also associated with a better prognosis [43]. Cancer-associated chronic inflammation initiated by epithelial cancer cells and stromal/immune cells overexpressing TLR9, is amplified and sustained by a chemokine inducer composed of activated NF-kB and STAT3 [44,45] which may promote cancer progression and therapeutic resistance [46].…”