Programmed death-ligand 1 (PD-L1) expression in malignant and benign cervical and breast cancers

Background: Programmed death-ligand 1 (PD-L1) expression has become a valuable biomarker for guiding immunotherapy selection in various cancers, including breast and cervical malignancies.Objective: This study aimed to investigate the immunohistochemical expression of PD-L1 in malignant and benign breast and cervical cancers.Methods: This retrospective study involved the analysis of 40 formalin-fixed paraffin-embedded tissue blocks, with 20 blocks from breast cancer patients and 20 from cervical cancer patients.Immunohistochemical analysis was performed via the avidin-biotin immunoperoxidase method to detect PD-L1 expression.The expression was assessed using a semi-quantitative method, grading the staining intensity and the percentage of stained cells per field.The stained sections were observed under a Leica microscope (Leica DM750, Switzerland) connected to a digital camera (Leica ICC50).Results: PD-L1 expression was greater in cervical cancer than in breast cancer.In breast cancer, benign cases mostly presented negative PD-L1 expression, with a mean percentage reactivity (MPR) of 14.8%, whereas malignant cases presented mild expression, with an MPR of 46.4%.In cervical cancer, benign cases were mainly negative, with an MPR of 18.4%, whereas malignant cases displayed mild to moderate PD-L1 expression, with an MPR of 71.3%. Conclusion:PD-L1 expression was more pronounced in cervical cancer than in breast cancer.The elevated levels of PD-L1 in cervical cancer suggest that this type of cancer may be more responsive to immunotherapeutic interventions targeting the PD-L1 pathway compared to breast cancer.Recognising these differences is crucial for tailoring treatment plans and implementing personalised medicine strategies for each specific cancer type.