Reviewing the Role of PD-L1 in Patients With Urothelial Carcinoma

In patients with urothelial carcinoma (UC), the relationship between PD-L1 and PD-1 leads to the inaction of T cells across the microenvironment and the evasion of host immune response.

A hospital-based observational study from Anushweta Singh, MD, and colleagues published in Cureus investigated the role of PD-L1 in patients with UC and analyzed its expression using histomorphological parameters.

Researchers evaluated the data of 50 specimens from patients who underwent transurethral resection of urinary bladder tumor (TURBT) and cystectomy for UC between 2022 and 2023. Immunohistochemistry (IHC) was completed through PD-L1 with rabbit antihuman PD-L1 monoclonal antibody.

Of the 50 cases, 35 (75%) were papillary type, 28 (56%) were high grade, and 30 were non-muscle invasive. Fifteen of the specimens demonstrated PD-L1 positivity, while 55% of the muscle invasive bladder cancer cases reported PD-L1 positivity.

Among the 20 muscle invasive specimens, 11 (55%) demonstrated PD-L1 positivity. Dr. Singh and colleagues also reported that the majority of the 30 non-muscle invasive cases were PD-L1 negative, with 4 cases showing PD-L1 expression. Researchers noted that this finding was statistically significant.

Fifteen (30%) of the specimens demonstrated PD-L1–positive expression, including 13 (37%) of the 35 infiltrating papillary UC cases, 1 (10%) of the 10 UC cases with lymphoepithelial variant, and 1 (20%) of the 5 cases with squamous differentiation.

Investigators noted that there was no significant relationship between tumor grade and PD-L1 positivity (P=.32).

“PD-L1 expression by IHC staining can differentiate between muscle invasive and non-muscle invasive UC cases,” investigators wrote. “This observation allows for further exploring the potential role of immune checkpoint inhibitors in adjuvant and neoadjuvant therapy, especially in muscle invasive cases of UC.”