Leukoplakia of oral cavity and urinary bladder are premalignant to squamous carcinoma.

A critical work published by Panchannavar on the close link between oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC), the expression of epithelial mesenchymal transition proteins ZEB1 and E-cadherin would predict the progression of OLK to OSCC. In connection with similar clinical status, there are cumulative data that the urinary bladder leukoplakia (Bladder-LK) progress to invasive bladder squamous cell carcinoma (SCC) which does not response to local therapy that indicates immediate cystectomy, these findings were established with multiple publications with clinical follow-up that showed the progression of leukoplakia to SCC in both oral cavity and urinary bladder. Oral leukoplakia, oral SCC, Bladder-LK, urothelial carcinoma (UC) of the bladder, squamous differentiation of UC, and bladder-SCC showed expression of programmed cell death-ligand 1 (PD-L1). In recent years, immune checkpoint inhibitors immunotherapy for malignant tumors became a promising cancer immunotherapy. However, the role of PD-L1 inhibitors in OLK OSCC is controversial. Objectives are to highlight the rationale for prospective treatment of OLK and OSCC with PD-L1 inhibitors immunotherapy.