KRT14 is a promising prognostic biomarker of breast cancer related to immune infiltration

Background: Breast cancer (BC) is the leading cancer among women globally, which has the highest incidence and mortality rate in over a hundred countries. This study was intended to discover a new prognostic biomarker, facilitating personalized treatment approaches. Methods: RNA sequencing data from The Cancer Genome Atlas database and Gene Expression Omnibus database were utilized to download to evaluate expression levels and prognostic significance of Keratin 14 (KRT14). Methylation of KRT14 was also assessed. The CIBERSORT and single-sample gene set enrichment analysis algorithms were applied to explore the connection between KRT14 and the tumor microenvironment. Primary drugs' sensitivity and potential small molecule therapeutic compounds were analyzed through the "pRRophetic" R package and the Connectivity Map. The prognostic value of KRT14 was additionally corroborated through a comparison of protein levels in peritumoral and cancerous tissues via immunohistochemistry. Moreover, an immune-related prognostic model based on KRT14 was designed to enhance the prediction accuracy for the prognosis of BC patients. Results: The study found that KRT14 expression was generally downregulated in BC, correlating strongly with poor prognosis. Compared to normal tissues, the methylation level of KRT14 was higher in BC tissues. Lower expression of KRT14 was linked to decreased anti-tumoral immune cells infiltration and increased immunosuppressive cells infiltration. Sensitivity to various key therapeutic drugs was lower in groups with diminished KRT14 expression. In addition, several potential anti-BC small molecule compounds were identified. The model designed in this study significantly enhanced the predictive capability for BC patients compared to predictions based solely on KRT14 expression levels. Conclusion: Overall, KRT14 was closely correlated with the prognosis in BC, making it a reliable biomarker.