High infiltration of mast cells is associated with improved response to adjuvant chemotherapy in gallbladder cancer

Abstract

Recent studies have reported that tumor-infiltrating mast cells (TIM) play an important role in tumor regression, but the effect of TIM in gallbladder cancer (GBC) remains unclear. The present study aims to investigate the prognostic value of TIM in GBC patients and its responsiveness to gemcitabine-based adjuvant chemotherapy (ACT). A total of 298 GBC patients from Zhongshan Hospital were recruited for this study. TIM infiltration was measured by immunohistochemical staining. Accumulation of TIM is significantly associated with prolonged overall survival in GBC patients. The benefit from gemcitabine-based ACT was superior among patients with high infiltration of TIM with GBC. Multivariate analysis identified TIM infiltration as an independent prognostic factor for overall survival. A heatmap showed that TIM-activated gene signatures were positively correlated with CD8+ T cells' gene signatures. Gene set enrichment analysis (GSEA) suggested that TIM was related to multiple T cell-related processes and signaling pathways, including the interferon gamma signaling pathway and the leukocyte migration signaling pathway. It was confirmed that CD8+ T cell infiltration was positively correlated with high TIM infiltration in tissue microarray (TMA), suggesting that TIM infiltration was linked to the immune surveillance in GBC. TIM can be used as an independent prognostic factor and a predictor of therapeutic response of gemcitabine-based ACT in GBC patients, which may mediate immune surveillance by recruiting and activating CD8+ T cells in GBC.

Keywords: adjuvant chemotherapy; gallbladder cancer; prognosis; tumor immune; tumor-infiltrating mast cells.

Figure 1

Evaluation of tumor‐infiltrating mast cells (TIM) by immunohistochemical staining in gallbladder cancer (GBC) patients. A, Representative immunohistochemistry images of TIM infiltration in different tumor tissues. B, Distribution of TIM in different TNM stages of Zhongshan cohort. C‐F, Kaplan‐Meier survival analysis of overall survival in all patients (C), patients who received adjuvant chemotherapy (ACT) (D), patients with TIM high (E) and patients with TIM low (F)

Figure 2

Tumor‐infiltrating mast cell (TIM) accumulation defines the immune surveillance context. A, Heatmap of CD8+ T cell signatures and Treg signatures in activated TIM gene signature tumors. B, Gene set enrichment analysis (GSEA) revealed an enrichment of the biology pathway involved in TIM high tumors. NES, normalized enrichment score. C, Volcano plot shows differential gene expression involved in CD8+ T cell reaction between TIM low and high groups. mRNA levels with a P < 0.05 and fold change ≥2 or ≤0.5 were perceived as differentially expressed

Figure 3

Correlation between tumor‐infiltrating mast cells (TIM) and tumor‐infiltrating lymphocytes in gallbladder cancer (GBC). A, Representative immunohistochemistry images of CD8 +T cell and Treg infiltration in corresponding low (left upper) and high (left lower) TIM infiltration patients. B‐D, Correlations assessed by Spearman analysis between TIM and tumor‐infiltrating lymphocyte immunohistochemistry score in GBC: (B) CD8+ T cells, (C) Treg and (D) CD8/Treg ratio

Figure 4

Kaplan‐Meier survival analysis of overall survival (OS) according to tumor‐infiltrating mast cells (TIM) and CD8+ T cells. A, Kaplan‐Meier survival analysis of OS in all patients, B, Patients who received adjuvant chemotherapy (ACT)