Introduction:

Adaptive anti-tumor immunity can be orchestrated by lymph node-like immune cell aggregates within the tumor microenvironment (TME) called tertiary lymphoid structures (TLSs). TLSs are postulated to be the gateway of lymphocyte infiltration into the TME, and are privileged sites for coordinated tumor antigen presentation and lymphocyte priming, differentiation, and proliferation, leading to a robust tumor-specific immune response. A 12-chemokine metagene grouping (12-CK score) has previously been described that correlates with the presence of TLSs in other solid tumor types. In this study, we explored the prognostic implication of the 12-CK score in bladder cancer and its correlation with the presence of TLSs.  

Methods:

Cystectomy specimens from 132 patients with bladder cancer were arrayed on Affymetrix microarrays. 12-CK scores were normalized with >1 denoting high scores (12-CK^Hi).  Immunohistochemistry (IHC) antibody staining was performed for DC-LAMP, CD20, CD4, and CD8. A GU pathologist scored TLSs into Types I-III, with type III representing fully developed TLSs. The Fisher’s exact test was used to test the associations between the 12-CK scores and the type of lymphoid aggregate. Overall survival was estimated using the Kaplan Meier method. Findings were validated using 12-CK scores extracted from TCGA transcriptome sequencing data and the IMvigor210CoreBiologies package.

Results:

Twenty-five (n=25/132) patients were classified as 12CK-High. Pathologic review of 43 bladder tumor specimens confirmed higher levels of Type III TLS patients (33% vs. 9%, p=0.03), B cells (p=0.002), CD8 T cells (p=0.01), and activated DC (p=0.01) in 12-CK^Hi compared to 12-CK^Lo. 12-CK^Hi was found to have a progression-free survival (PFS, HR 0.29, p=0.003), disease specific survival (DSS, HR 0.29, p=0.004), and overall survival (OS, HR 0.55, p=0.03) advantage compared to 12-CK^Lo in the Moffitt patient cohort (Fig1a-c). These results were validated using the publically available RNA expression data from TCGA. TCGA patients with 12-CK^Hi (18%,n=72) had improved PFS ( HR 0.55, p=0.007), DSS (HR =0.40, p=0.002), and 0S (HR=0.59, p=0.01) (fig1d-f). From the IMVIGOR-210 patients who were 12-CK^Hi were more likely to have a complete response (p< 0.05) and had a 11.2mo OS benefit after treatment using atezolizumab (Fig1g-h).

Conclusion:

Three important findings emerged from the current study: 12CK-High scores corresponded with formation of TLS in the TME; favorable prognosis in surgically treated MIBC patients; and CR in atezolizumab-treated patients. The findings herein suggest the 12CK gene signature to be a clinically actable biomarker for predicting response to immune checkpoint blockade. We believe the 12CK signature may serve as an important tool to refine patient selection for immune checkpoint blockade treatment.

Funding: N/A