CCL2 Expression in Tumor Cells and Tumor-Infiltrating Immune Cells Shows Divergent Prognostic Potential for Bladder Cancer Patients Depending on Lymph Node Stage

Abstract

Bladder cancer (BCa) is the ninth most commonly diagnosed cancer worldwide. Although there are several well-established molecular and immunological classifications, markers for tumor cells and immune cells that are associated with prognosis are still needed. The chemokine CC motif ligand 2 (CCL2) could be such a marker. We analyzed the expression of CCL2 by immunohistochemistry (IHC) in 168 muscle invasive BCa samples using a tissue microarray. Application of a single cut-off for the staining status of tumor cells (TCs; positive vs. negative) and immune cells (ICs; ≤6% of ICs vs. >6% of ICs) revealed 57 cases (33.9%) and 70 cases (41.7%) with CCL2-positive TCs or ICs, respectively. IHC results were correlated with clinicopathological and survival data. Positive CCL2 staining in TCs was associated with shorter overall survival (OS), disease-specific survival (DSS), and relapse-free survival (RFS) (p = 0.004, p = 0.036, and p = 0.047; log rank test) and appeared to be an independent prognostic factor for OS (RR = 1.70; p = 0.007; multivariate Cox’s regression analysis). In contrast, positive CCL2 staining in the ICs was associated with longer OS, DSS, and RFS (p = 0.032, p = 0.001, and p = 0.001; log rank test) and appeared to be an independent prognostic factor for DSS (RR = 1.77; p = 0.031; multivariate Cox’s regression analysis). Most interestingly, after separating the patients according to their lymph node status (N0 vs. N1+2), CCL2 staining in the ICs was differentially associated with prognosis. In the N0 group, CCL2 positivity in the ICs was a positive independent prognostic factor for OS (RR = 1.99; p = 0.014), DSS (RR = 3.17; p = 0.002), and RFS (RR = 3.10; p = 0.002), whereas in the N1+2 group, CCL2 positivity was a negative independent factor for OS (RR = 3.44; p = 0.019)) and RFS (RR = 4.47; p = 0.010; all multivariate Cox’s regression analyses). In summary, CCL2 positivity in TCs is a negative prognostic factor for OS, and CCL2 can mark ICs that are differentially associated with prognosis depending on the nodal stage of BCa patients. Therefore, CCL2 staining of TCs and ICs is suggested as a prognostic biomarker for BCa patients.

Analysis of CXCL9, PD1 and PD-L1 mRNA in Stage T1 Non-Muscle Invasive Bladder Cancer and Their Association with Prognosis

“…Similar to Huang et al we showed a correlation between the mRNA of PD-L1 and C-C chemokines ( CCL2, CCL3, CCL8 and CCL18 ) [ 30 , 31 ]. A correlation between PD1 and PD-L1 mRNA was previously shown by both Huang et al [ 31 ] and by us [ 28 ].…”

Immune Cell-Associated Protein Expression Helps to Predict Survival in Muscle-Invasive Urothelial Bladder Cancer Patients after Radical Cystectomy and Optional Adjuvant Chemotherapy

“…Based on our previous results [ 9 , 13 ], we hypothesized that it would be possible to further substratify patients into groups using immune markers. We sought to identify patients with an N0 status and/or pT2 tumors that might benefit from not receiving chemotherapy.…”

“…Recently, we found that the expression of the immune cell marker chemokine CC motif ligand 2 (CCL2) was differentially associated with prognosis depending on the lymph node stage. In the N0 group, CCL2 positivity in immune cells (ICs) was a positive independent prognostic factor for OS, DSS, and recurrence-free survival (RFS), whereas, in the N1 + 2 group, CCL2 positivity was a negative independent factor for OS and RFS [ 13 ]. Based on this finding, we were interested in whether the expression of immune cell markers could be helpful in the prediction of the chemotherapy treatment response in MIBC patients stratified by their nodal stage or tumor stage.…”

“…CCL2 has been shown to be expressed in tumor-associated macrophages [ 15 , 16 , 17 ]. In addition, we showed a strong correlation of CCL2 with the expression of programmed cell death 1 ligand 1 (PD-L1), which is expressed by several immune cells, such as T-cells, natural killer cells, macrophages, myeloid dendritic cells, and B-cells [ 13 ]. This finding suggests that CCL2 expression is not restricted to only macrophages but is also part of the concerted immune cell response.…”

“…Recently, we showed that higher CD68 and CCL2 staining in immune cells was associated with better DSS and RFS in MIBC patients, whereas CD163 expression was not associated with prognosis (OS, DSS, or RFS) [ 13 ]. Our working hypothesis is that the presence of tumor-infiltrating immune cells, here represented as macrophages characterized by the markers CD68, CD163, and CCL2, could be associated with a better prognosis, but that chemotherapy may not add an advantage for prognosis.…”