Identification of LAT/ZAP70 characterized immune subtypes of prostate cancer.

Background: While immunotherapy has shown potent efficacy in clinical practices, patient selection to receive checkpoint blockade is still challenging in prostate cancer (PCa). LAT and ZAP70 functions in lymphocyte activation and plays a critical role in T cell receptor (TCR) signal transduction. However, PCa genomic and clinical data regarding the role of LAT and ZAP70 are limited. We aim to identify and characterize LAT/ZAP70 defined subtypes of PCa.

Methods: We elaborated the TCGA PCa data and metastatic castration-resistant prostate cancer (mCRPC) RNA-seq data bioinformatic analysis and systematically elucidated the role of intra-tumoral expressed LAT and ZAP70 in the progression-free survival and immunotherapeutic-related signals. LAT/ZAP70-associated immune infiltration was evaluated using bioinformatic tools. Immunohistochemical staining of serial sections was used to confirm the expression and distribution of LAT, ZAP70 and androgen receptor (AR) in PCa tissues.

Results: Specifically, LAT and ZAP70 revealed increased expressions in PCa when compared to normal tissues and positively associated with intra-tumoral immune cells infiltration. LAT/ZAP70 defined immune-high early-stage PCa revealed higher TP53 mutation frequency and poor prognosis. Transcriptome analysis indicated immune-related signals and CTLA4 expression were highly enhanced in immune-high PCa parallel with higher protein level of MYC and lower AR expression. In mCRPC, LAT/ZAP70 defined immune-high patients also revealed upregulated immune related signals, higher CTLA4 expression and DNA repair deficiency.

Conclusion: LAT/ZAP70 defined immune-high PCa linked to immune infiltration and predicts poor prognosis. Immune-high PCa may receive effective response from immune checkpoint inhibitor parallel with systemic treatment.