Clinical evaluation of a novel-developed clone 3E2 for the detection of PD-L1 expression status in lung adenocarcinoma.

BACKGROUND

Detecting programmed death-ligand 1 (PD-L1) expression helps identify patients likely to respond to PD-1/PD-L1 therapies. However, the high costs of PD-L1 assays, such as SP263 pharmDx, limit their widespread use, creating a need for cost-effective alternatives. This study evaluates the analytical performance and concordance of the newly developed 3E2 PD-L1 antibody with established clones in lung adenocarcinoma (LUAD).

METHODS

The 3E2 monoclonal antibody was developed using the hybridoma technique. Its performance was compared with that of the SP263, Cell Signaling Technology (CST) E1L3N, and Abcam 28-8 clones using immunohistochemistry on 101 LUAD samples. Concordance was assessed using Bland-Altman plots, confusion matrices, and quantitative analyses. Survival analysis was performed to investigate the correlation between PD-L1 expression detected by the 3E2 clone and treatment outcomes in patients undergoing immunotherapy.

RESULTS

Among 30 PD-L1 monoclonal antibodies generated via hybridoma, the 3E2 clone showed high sensitivity and specificity for PD-L1 detection. It exhibited strong concordance with Abcam 28-8 in positive (placenta) and negative (normal stomach mucosa) control tissues, as well as non-small cell lung cancer and melanoma samples (accuracy: 90.1%, κ: 0.797). Moderate agreement was observed with CST E1L3N (accuracy: 69.8%, κ: 0.401) and SP263 (accuracy: 55.4%, κ: 0.262), with higher PD-L1 expression detected by E1L3N and SP263. Bland-Altman analysis showed minimal bias between 3E2 and 28-8. Survival analysis revealed that patients with PD-L1 expression ≥ 5% (detected by 3E2) had significantly better outcomes (p = 0.021).

CONCLUSIONS

The 3E2 antibody demonstrates high concordance with Abcam 28-8, offering a potential cost-effective alternative for PD-L1 detection with preliminary prognostic value in immunotherapy-treated LUAD patients. Further validation is required to confirm its clinical utility.