Expression of JMJD5 was different in distinct human cancers
We investigated mRNA expression of JMJD5 in different cancers using TIMER obtained from The Cancer Genome Atlas tumor (TCGA) database containing cancerous and normal human tissues. The results revealed that mRNA expression of JMJD5 was significant higher in PRAD (**) and STAD (***), but lower in BRCA (*), GHOL (***), colon adenocarcinoma (COAD) (***), Kidney chromophobe cell carcinoma (***), LIHC (***), LUAD (·), LUSC (***) and Uterine corpus endometrial carcinoma (***), each compared to respective normal tissues. However, there was no difference between cancerous and normal tissues of mRNA expression of JMJD5 in bladder urothelial carcinoma (BLCA). Unfortunately, it was impossible to obtain the comparison results between cancerous and normal tissues in cervix squamous cell carcinoma (CESC), ovarian cancer (OV) and pancreas invasive ductal carcinoma (PAAD) due to the lack of normal tissues (Figure 1).
To confirm the JMJD5 protein expression and estimate its clinical significance in cancers, we explored the protein expression of JMJD5 in TMAs from 14 kinds of different cancers obtained from patients who had surgery in Huaihe Hospital of Henan University by using IHC analysis. The quantification of IHC was formalized into mean optical density detected by Image-Pro Plus software. As shown in (Figure 2A), the protein expression of JMJD5 was significant higher in BLCA (*), CESC (*), OV (*), PAAD (*), PRAD (**) and STAD (***) than in their respective normal tissues, but was significantly lower in BRCA (*), CHOL (*), KIRC (**), LIHC (*), LUAD (**) and LUSC (*) than in their each normal tissues (Figure 2B). JMJD5 protein level was higher in COAD than respective normal tissue, but there is no statistical significant difference (Figure 2A). Additionally, we found JMJD5 exists in different parts of tumor cells by IHC staining, either in nuclei or in cytoplasm, or in both. The JMJD5 protein expression was observed only in nuclei in BRCA and LUAD (Figure 2B), only in cytoplasm in COAD, OV, PAAD, PRAD, STAD and CHOL, kidney renal clear cell carcinoma (KIRC), LIHC, LUSC and Uterine corpus endometrial carcinoma (Figure 2A and B), and in both nuclei and cytoplasm in BLCA and CESC (Figure 2A).
Expression of JMJD5 can serve as prognostic marker in BRCA, LIHC, LUC and STAD
We proceeded to determine whether the expression of JMJD5 is associated with the prognosis of cancer patients via online resource of Kaplan-Meier Plotter, GEPIA and PrognoScan. Among the cancers (BLCA, BRCA, CESC, OV, PAAD, PRAD, STAD, CHOL, KIRC, LIHC, LUAD and LUSC) with significantly different expression of JMJD5, we identified JMJD5 as prognostic marker by analyzing relapse free survival (RFS) in BRCA (n=3955, RFS: HR=0.75, 95% CI from 0.67 to 0.83, log-rank P = 1.4e-07) (Figure 3A), LIHC (n=364, RFS: HR=0.6, 95% CI from 0.42 to 0.85, log-rank P =0.0033) (Figure3B), LUC (n=1927, RFS: HR=0.81, 95% CI from 0.71 to 0.92, log-rank P =0.001) (Figure3C) and STAD (n=881, RFS: HR=1.25, 95% CI from 1.05 to 1.49, log-rank P =0.011) (Figure3D). These results showed that the patients with significant higher expression of JMJD5 have an improved survival rate in BRCA, LIHC and LUC. On the contrary, the patients with low expression of JMJD5 were correlated with a better survival rate in STAD. In brief, the expression level of JMJD5 impacted RFS and could be served as prognostic marker in BRCA, LIHC, LUC and STAD.
Expression of JMJD5 was strongly correlated with tumor-infiltrating immune cells in BRCA, LIHC, LUAD, LUSC and STAD
To further explore the potential relationships between the expression of JMJD5 and infiltration of immune cells, we analyzed the correlation between JMJD5 expression and six tumor-infiltrating immune cells (B cells, CD4+ T cells, CD8+ T cells, macrophages, neutrophils, and myeloid dendritic cells) focusing on BRCA, LIHC, LUAD, LUSC and STAD. The results demonstrated that the expression level of JMJD5 has significant negative correlation with tumor purity, positive correlation with infiltration of B cell, CD4+ T cell, CD8+ T cell and macrophage and no relation with infiltrating of neutrophil, and myeloid dendritic cell in BRCA (Figure 4A). The expression level of JMJD5 has no relation with tumor purity and infiltrating of macrophage, neutrophil, and myeloid dendritic cell, but significant positive correlation with infiltration of B cell, CD4+ T cell and CD8+ T cell in LIHC (Figure 4B). The expression level of JMJD5 has significant negative correlation with tumor purity, positive correlation with infiltration of B cell, CD4+ T cell, macrophage, neutrophil and myeloid dendritic cell and no relation with CD8+ T cell in LUAD (Figure 4C). The expression level of JMJD5 has significant negative correlation with tumor purity, positive correlation with infiltration of B cell, CD4+ T cell, CD8+ T cell, macrophage, neutrophil and myeloid dendritic cell in LUSC (Figure 4D). The expression level of JMJD5 has no relation with tumor purity, but significant positive correlation with infiltration of B cell, CD4+ T cell, CD8+ T cell, macrophage and myeloid dendritic cell in STAD (Figure 4E). Taken together, the expression level of JMJD5 was strongly correlated with immune cells infiltration in BRCA, LIHC, LUAD, LUSC and STAD.
Correlation analysis between survival rate and immune cells infiltration in BRCA, LIHC, LUAD, LUSC and STAD
We analyzed the association between clinical outcome and abundance of six immune cells infiltration in TIMER database. Kaplan–Meier (KM) survival analyses displayed that the more amount of tumor-infiltrating B cells the longer survival rate in BRCA (log-rank P=0.046) and LUAD (log-rank P=0) (Figure 5A and C, labeled with blue box). The lower amount of tumor-infiltrating macrophages the longer survival rate in STAD (log-rank P=0.004) (Figure 5E, labeled with blue box). In addition to the tumors described above, the other immune cells tumor-infiltrating levels have no correlation with survival rate in the other types of tumors (Figure 5A-E). To sum up, B cells could be used as a prognostic marker for BRCA or LUAD and macrophages could be served as a prognostic marker for STAD.
Prognostic value of combinations of JMJD5 expression and tumor-infiltrating immune cells
To further investigate the prognostic value of combinations of JMJD5 expression and tumor-infiltrating immune cells. Here, we made a COX proportional hazards model analysis of clinical outcome, the immune cell infiltration and expression of JMJD5 in BRCA, LUAD and STAD. The KM plots curve showed that patients with low expression of JMJD5 have an improved survival rate comparing their tumor with higher B cell infiltration to lower B cell infiltration in BRCA (n=1100, OS: HR=0.658, P =0.0487) (Figure 6A) and LUAD (n=515, OS: HR=0.553, P =0.00415) (Figure 6B). The STAD patients with low expression of JMJD5 have a better survival rate comparing their tumor with lower macrophage infiltration to higher macrophage infiltration (n=415, OS: HR=1.7, P=0.02) (Figure 6C). The combination of JMJD5 expression with either B cells tumor infiltration or macrophages tumor infiltration could be served as a new tumor prognostic value.