Bladder cancer (BCa) is a prevalent malignancy with challenging prognosis and management. Lactylation, a novel post-translational modification, is dysregulated in various cancers. This study investigates lactylation-derived signature for prognostic assessment and treatment decisions in BCa.

We used immunohistochemistry (IHC) to assess tissue microarrays (TMA) and Western blot to investigate BCa cell lines to evaluate overall lactylation. The Cancer Genome Atlas (TCGA) cohort was categorized into two clusters based on lactylation-related genes (LRGs) using consensus clustering. We analyzed survival rates, clinical features, tumor microenvironment (TME), and responses to immunotherapy and chemotherapy. A 3-gene lactylation-related gene risk score (LRGRS), based on AHNAK, ALDH1A1, and CALR, was developed using least absolute shrinkage and selection operator (LASSO) regression with 10-fold cross-validation, random forest (RF), and support vector machine recursive feature elimination (SVM-RFE), and was validated in Gene Expression Omnibus (GEO) datasets and further characterized in single-cell datasets. Subsequently, LRGRS was analyzed alongside clinical characteristics, mutation profiles, biological functions, immune cell infiltration, immunotherapy responses, and drug sensitivity. Core genes were examined in vitro.

Our findings demonstrated a significant increase of pan-lysine lactylation (Pan-kla) in BCa. Through the integration of TCGA datasets, GEO datasets, single-cell datasets, and in vitro studies, we found and validated an LRGRS model including three genes capable of predicting the prognosis of BCa patients. Significant differences were noted for clinical features, biological functioning, immune cell infiltration, immune checkpoint expression, immunotherapy response, and drug sensitivity among various risk categories.

In conclusion, our research presents LRGRS as an innovative and dependable prognostic biomarker for BCa, capable of precisely and consistently forecasting survival rates, informing personalised therapy for BCa patients, and offering new therapeutic methods for the condition.