Programmed Death Ligand-1 Testing in Adenocarcinoma Lung: A Comparative Study of Cell Block versus Biopsy
Saumya Shukla1, Rahul K Pandey1, Vani Gupta1
1Department of Pathology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
Background:
Immunotherapy currently stands as a novel treatment option, specifically in cases of advanced non-small cell lung carcinoma (NSCLC). Expression of programmed death ligand-1 (PD-L1) in tumor cells forms the mainstay for the use of anti-PD-L1 monoclonal antibodies in the treatment of NSCLC.
Aims:
The objectives of the study were to assess utility of cell blocks for testing of PD-L1 in adenocarcinoma lung and to compare the expression of PD-L1 in cell blocks and the corresponding biopsy specimens.
Materials And Methods:
The current study was a prospective case series that included 20 cases of NSCLC-adenocarcinoma lung. Cases included in the study had biopsies performed from lung masses, along with which cell blocks were prepared from fine needle aspiration cytology (FNAC) samples. Testing for PD-L1 was done using the monoclonal PD-L1 antibody, SP-263 clone on the Ventana Benchmark XT system. PD-L1 expression was assessed only in the tumor cells, and cases with >1% expression, cytoplasmic or membranous, in tumor cells were categorized as positive.
Results:
PD-L1 expression was identified in the biopsy samples of tumor cells of 20% of cases (n = 4/20). In the corresponding cell blocks, PD-L1 expression was identified in the tumor cells of 15% of cases (n = 3/20). Sensitivity and specificity of cell blocks were 75% and 100%, respectively. Positive and negative predictive values were 100% and 94.12%, respectively.
Conclusion:
PD-L1 testing has both predictive and prognostic implications. PD-L1 testing in cell block samples is a potential alternative, specifically in cases where biopsy tissue is minimal or unavailable.
Insights
Cell blocks are a viable alternative for programmed death ligand-1 (PD-L1) testing in non-small cell lung carcinoma (NSCLC) when biopsy tissue is limited. This method shows high specificity and predictive values for PD-L1 expression in lung adenocarcinoma.
Area of Science:
- Oncology
- Pathology
- Immunotherapy
Background:
- Immunotherapy offers a novel treatment for advanced non-small cell lung carcinoma (NSCLC).
- Programmed death ligand-1 (PD-L1) expression in tumor cells is crucial for anti-PD-L1 antibody efficacy in NSCLC treatment.
Purpose of the Study:
- To evaluate the utility of cell blocks for PD-L1 testing in lung adenocarcinoma.
- To compare PD-L1 expression between cell blocks and corresponding biopsy specimens.
Main Methods:
- Prospective case series of 20 NSCLC-adenocarcinoma lung cases.
- PD-L1 testing performed on biopsy and fine needle aspiration cytology (FNAC)-derived cell block samples.
- SP-263 clone antibody used on Ventana Benchmark XT system; >1% tumor cell expression defined as positive.
Main Results:
- PD-L1 expression detected in 20% of biopsy samples (4/20) and 15% of cell blocks (3/20).
- Cell blocks demonstrated 75% sensitivity and 100% specificity for PD-L1 detection.
- Positive and negative predictive values for cell blocks were 100% and 94.12%, respectively.
Conclusions:
- PD-L1 testing holds significant predictive and prognostic value in cancer treatment.
- Cell block samples represent a practical alternative for PD-L1 testing, especially when biopsy material is scarce.
