PD-L1 Expression in Locally Advanced Cervical Cancer: A Pilot Cross-Clone Comparison Study

Area of Science:

• Oncology
• Immunology
• Pathology

Background:

• Immunotherapy trials for locally advanced cervical cancer report varying PD-L1 positivity rates.
• Discrepancies between clinical trials and academic initiatives necessitate cross-clone validation of PD-L1 testing.

Purpose of the Study:

• To compare PD-L1 positivity using two different antibody clones (SP142 and 22C3) in locally advanced cervical cancer.
• To assess the impact of clone selection on PD-L1 expression and its implications for immunotherapy.

Main Methods:

• A pilot cohort of FIGO 2018 stage III cervical cancer patients was analyzed.
• PD-L1 immunohistochemistry (IHC) was performed using clones SP142 and 22C3.
• Positive and negative predictive values were calculated for each clone against the other.

Main Results:

• Overall PD-L1 positivity rates were similar (33.3% SP142 vs. 36.6% 22C3).
• Significant patient-level heterogeneity was observed, with 30% of SP142-negative samples testing positive for 22C3.
• Predictive values varied substantially between clones, indicating clone-dependent interpretation.

Conclusions:

• Different antibody clones for PD-L1 IHC yield heterogeneous results in cervical cancer.
• Clone selection significantly impacts patient stratification for immunotherapy.
• Further research is crucial to standardize PD-L1 assessment and optimize treatment selection.