Gen Lin

Comparison of 22C3 PD-L1 Expression between Surgically Resected Specimens and Paired Tissue Microarrays in Non–Small Cell Lung Cancer

Introduction: The extent to which intratumoral heterogeneity of programmed death ligand 1 (PD‐L1) expression causes discordance of PD‐L1 expression between paired samples remains unclear. Here, PD‐L1 status was compared between whole sections from NSCLCs and the corresponding tissue microarrays (TMAs) serving as surrogate biopsy specimens. Methods: PD‐L1 expression was evaluated by 22C3 immunohistochemistry assay on 190 archival surgical specimens and matched to the TMA results. PD‐L1 expression was determined by the tumor proportion score (TPS) and classified as TPS lower than 1%, TPS of 1% to 49%, and TPS of 50% or higher. Agreement statistics were used. Results: The percentage of PD‐L1 expression on tumor cells differed greatly between individual TMAs and matched surgical specimens. When PD‐L1 TPS was adopted, a total of 36 of 190 discordance cases (18.9%) were observed, with a &kgr;‐value of 0.630 between paired samples. The TMAs underestimated or overestimated PD‐L1 status in 19 of 36 (52.8%) and 17 of 36 (47.2%) of the matched surgical specimens, respectively (p = 0.118). The discordance rate was much lower in cases with a PD‐L1 TPS lower than 1% compared with in cases with a TPS of 1% to 49% and TPS of 50% or higher (18.4% versus 56.7% and 43.3%, p < 0.001). When a TPS of 50% or higher was used as the cutoff, the discordance rate of PD‐L1 TPS less than 50% was further reduced to 7.5%. Such discrepancies were due mainly to intratumoral heterogeneity of PD‐L1 expression and nonsignificant association with clinicopathological features. Conclusions: PD‐L1 expression in TMAs correlates moderately well with that in the corresponding surgical specimens, indicating that evaluating PD‐L1 expression in diagnostic biopsy specimens could be misleading in defining sensitivity to pembrolizumab treatment yet may be reliable as a way to exclude patients with a PD‐L1 TPS less than 50% from first‐line pembrolizumab treatment.

Prognostic significance of PD-L1 expression and tumor infiltrating lymphocyte in surgically resectable non-small cell lung cancer

Programmed death ligand 1 (PD-L1) expression is a predictive biomarker of the success of PD-1/PD-L1 inhibitor therapy for patients with advanced non-small cell lung cancer (NSCLC) but its role as a prognostic marker for early stage resectable NSCLC remains unclear. Here, we studied PD-L1 expression and tumor infiltrating lymphocytes (TILs) in surgically resectable NSCLC and correlate the finding with clinicopathological features and patient outcomes. Total of 170 archival samples of resectable NSCLC were probed for PD-L1 expression using the clone 22C3 pharmDx kit. The PD-L1 expression was determined by the Tumor Proportion Score (TPS) and classified into TPS <1%, TPS 1 to 49% and TPS ≥50%. The scoring of TILs was from hematoxylin & eosin stained tissue sections using a system for standardized evaluation of TILs in breast cancer. PD-L1 expression was compared with clinical pathological characteristics and survival outcome. Expression of PD-L1 scores of TPS ≥50%, TPS 1 to 49% and TPS <1% were observed in 10.6%, 24.7% and 64.7% of the 170 archival samples, respectively. Positive PD-L1 expression was significantly higher in patients with squamous carcinoma, in those with higher TNM stage and with the presence of TILs. Neither the PD-L1 expression, TIL status, nor their combination was an independent prognosis biomarker of survival when the data was subjected to either univariate or multivariate analysis. The incidence of PDL1 expression appears to be lower in patient with early stage resectable lung cancer. PD-L1 expression and TILs are not prognostic indicators of survival outcome in this population.

Comparison of the c-MET gene amplification between primary tumor and metastatic lymph nodes in non-small cell lung cancer

c‐MET has recently been identified as a promising novel target in non‐small cell lung cancer (NSCLC). We detected the consistency of c‐MET gene amplification in metastatic lymph nodes and tumor tissues of NSCLC patients and discuss the clinical application value of c‐MET gene amplification in metastatic lymph nodes.

Assessment of Concordance between 22C3 and SP142 Immunohistochemistry Assays regarding PD-L1 Expression in Non-Small Cell Lung Cancer

Different anti-PD-1 and anti-PD-L1 antibodies bind different epitopes. However, whether the results from the SP142 and 22C3 immunochemistry (IHC) assays can be interchanged to determine patient eligibility for immunotherapy remains largely unknown. Histologic sections from 135 tumor samples were probed with both 22C3 and SP142 antibodies. The concordance of PD-L1 expression determined by the two assays was assessed. Additionally, we evaluated the association of PD-L1 expression detected by different assays with clinicopathological features and prognosis. In total, 105 (77.78%) of 135 samples evaluated by the 22C3-IHC platform produced the same results with the SP142-IHC platform (Kappa value: 0.481, pu2009<u20090.001). In addition, 69 (51.11%) of 135 samples evaluated by the SP142-IHC platform produced the same results with the 22C3-IHC platform (Kappa value: 0.324, pu2009<u20090.001). PD-L1 expression based on the 22C3-IHC assay was significantly correlated with smoking status, whereas that based on the SP142-IHC assay was correlated with smoking status, sex, and histology. Compared to the SP142-IHC assay, the 22C3-IHC assay usually resulted in an underestimation of PD-L1 expression in tumor cells and immune cells. Thus, the results from the two assays cannot be interchanged. Our data also suggest that the use of different reagents may account for inconsistencies in the literature regarding the association between PD-L1 expression and clinicopathological features.

Analysis of H3K27me3 expression and DNA methylation at CCGG sites in smoking and non-smoking patients with non-small cell lung cancer and their clinical significance

Smoking frequently leads to epigenetic alterations, including DNA methylation and histone modifications. The effect that smoking has on the DNA methylation levels at CCGG sites, the expression of trimethylation of histone H3 at lysine 27 (H3K27me3) and enhancer of zeste homolog 2 (EZH2), and their interactions in patients with non-small cell lung cancer (NSCLC) were analyzed. There were a total of 42 patients with NSCLC, 22 with adenocarcinomas and 20 with squamous cell carcinomas enrolled in the present study. Expression of H3K27me3, EZH2 and proliferating cellular nuclear antigen (PCNA) were immunohistochemically detected. DNA methylation at CCGG sites was evaluated via histoendonuclease-linked detection of DNA methylation sites. The apoptotic index of cancerous tissues obtained from patients of different smoking statuses was evaluated via the terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labeling method. The association with clinicopathological data was calculated relative to different smoking statuses. Compared with the non-smokers, smokers with NSCLC exhibited a significantly lower apoptotic index (P<0.05), and frequently had a lower level of DNA methylation at CCGG sites, lower H3K27me3 expression and a higher EZH2 expression (P<0.05). DNA methylation levels at CCGG sites were negatively correlated to the Brinkman index (P=0.017). Furthermore, there was a parallel association between the H3K27me3 and EZH2 expression levels in the majority of smokers, whereas in the majority of non-smokers, there was a diverging association (P=0.015). There was a diverging association between the PCNA and EZH2 expression levels in the majority of smokers; however, in the majority of non-smokers, there was a parallel association (P=0.048). In addition, the association between the CCGG methylation ratio and immunohistochemical expression of H3K27me3 was a parallel association in the majority of smokers, while in the majority of non-smokers there was a diverging association (P=0.049). Conclusively, patients with NSCLC and different smoking statuses exhibit different epigenetic characteristics. Additionally, DNA methylation levels at the CCGG sites may have the ability to determine associations between the expression levels of H3K27me3, EZH2 and PCNA.

Co-expression of NF-κB-p65 and phosphorylated NF-κB-p105 is associated with poor prognosis in surgically resectable non-small cell lung cancer

Nuclear factor‐kappa B (NF‐κB) as a prognostic marker remains unclear in non‐small cell lung cancer (NSCLC). Here, we studied NF‐κB‐p65 (p65) expression and phosphorylated NF‐κB‐p105 (p‐p105) expression in NSCLC and correlated the finding with overall survival (OS) and clinicopathological features. A total of 186 archival samples from patients with surgically resectable NSCLC were probed with p65 and p‐p105 (Ser 932). The p65‐positive expression and p‐p105‐positive expression were defined as distinct nuclear p65 and cytoplasmic p‐p105 labelling in at least 1% of tumour cells, respectively. The positive staining of p65 alone, p‐p105 alone and co‐expression of p65 and p‐p105 were observed in 61 (32.8%), 90 (48.4%) and 35 (18.8%) patients, respectively. Co‐expression of p65 and p‐p105 but not of either p65 or p‐p105 alone was associated with a poor prognosis. Patients with co‐expression of p65 and p‐p105 had a shorter OS than others, median OS 26.5 months versus 64.1 months, HR 1.85 (95% CI: 1.18–2.91), P = 0.007. There was no statistically significant association between clinicopathological characteristics and either p65 or p‐p105 alone or co‐expression of p65 and p‐p105. This indicates that co‐expression of p65 and p‐p105 was a poor prognostic factor, and pathologic studies of NF‐κB expression could include multiple pathway components in NSCLC.

Advances in Treatment of Brain Metastases from Primary Non-small Cell Lung Cancer

Metastatic tumors involving the brain are an important complication in the overall management of non-small cell lung cancers. Surgery and radiation remain the cornerstones of the therapy, however, the burgeoning knowledge of tumor biology has facilitated the entry of systemically administered therapies into the clinic. This review mainly summarizes the current applications of these data to surgery, radiation therapy, chemotherapy and targeted therapy.