Assessment of programmed cell death ligand-1 expression by 4 diagnostic assays and its clinicopathological correlation in a large cohort of surgical resected non-small cell lung carcinoma.

Immune checkpoint blockade targeting the PD-1/PD-L1 axis has recently demonstrated efficacy and promise in cancer treatment. Appropriate biomarker selection is therefore essential for improving treatment efficacy. However, the establishment of PD-L1 assay in pathology laboratories is complicated by the presence of multiple testing platforms using different scoring systems. Here we assessed the PD-L1 expression in 713 consecutive non-small cell lung carcinomas by four commercially available PD-L1 immunohistochemical assays, namely, 22C3, 28-8, SP142 and SP263. The analytical performances of the four assays and diagnostic performances across clinically relevant cutoffs were evaluated. The prevalence of PD-L1 (22C3) expression was 21% with a ≥50% cutoff and 56% with a ≥1% cutoff. High PD-L1 expression (using a ≥50% cutoff) was significantly associated with male sex (P = 0.001), ever smoking history (P < 0.001), squamous cell carcinoma (P = 0.001), large cell carcinoma (P < 0.001), lymphoepithelioma-like carcinoma (P = 0.006), sarcomatoid carcinoma (P < 0.001), mutant KRAS (P = 0.005) and wild-type EGFR (P = 0.003). Elevated PD-L1 expression was also significantly associated with shorter survival in patients with adenocarcinoma (log-rank P = 0.026) and remained an independent prognostic factor by multivariable analysis. Among the four assays, 22C3, 28-8 and SP263 were highly concordant for tumor cell scoring. With a cutoff of ≥50% (i.e., the threshold for first-line patient selection), inter-rater agreement was high among the three assays with percentage agreement >97%. In conclusion, three PD-L1 assays showed good analytical performance and a high agreement with each other, but not all cases were correctly classified using the same clinical cutoff. Further studies comparing the predictive value of these assays are required to address the interchangeability of these assays for clinical use.

The Landscape of Actionable Molecular Alterations in Immunomarker-Defined Large-Cell Carcinoma of the Lung.

INTRODUCTION: Patients with pulmonary large-cell carcinoma (LCC) have poor prognosis and limited treatment options. The identification of clinically actionable molecular alterations helps to guide personalized cancer treatment decisions. PATIENTS AND METHODS: A consecutive cohort of 789 resected NSCLC cases were reviewed. Fifty-nine NSCLC cases lacking morphologic differentiation, accounting for 7.5% of all resected NSCLCs, were identified and further characterized by immunohistochemistry according to the 2015 WHO lung tumor classification. Molecular alterations were investigated by multiple technologies including target capture sequencing, immunohistochemistry, and fluorescence in situ hybridizations. RESULTS: Of 59 NSCLC cases lacking morphologic differentiation, 20 (33.9%) were reclassified as adenocarcinoma (LCC-AD), 14 (23.7%) as squamous cell carcinoma (LCC-SqCC), and 25 (42.4%) as LCC-Null. Approximately 92% of LCC-Null, 95% of LCC-AD, and 86% of LCC-SqCC harbored clinically relevant alterations. Alterations characteristic of adenocarcinoma (EGFR, KRAS, ALK receptor tyrosine kinase [ALK], ROS1, and serine/threonine kinase 11 [STK11]) were detected in the LCC-AD subgroup but not in LCC-SqCC, whereas squamous-lineage alterations (phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit alpha [PIK3CA], SRY-box 2 [SOX2], fibroblast growth factor receptor 1 [FGFR1], and AKT1) were detected in the LCC-SqCC subgroup but not in the LCC-AD group. Although some LCC-Null tumors displayed a genetic profile similar to either adenocarcinoma or squamous-cell carcinoma, more than half of the LCC-Null group were completely devoid of recognizable lineage-specific genetic profiles. High programmed death ligand 1 expression and high frequency of cell cycle regulatory gene alterations were found in the LCC-Null group offering alternative options of targeted therapy. CONCLUSIONS: This comprehensive molecular study provided further insight into the genetic architecture of LCC. The presence of clinically actionable alterations in a majority of the tumors allowed personalized treatment to emerge.

MET Amplification and Exon 14 Splice Site Mutation Define Unique Molecular Subgroups of Non-Small Cell Lung Carcinoma with Poor Prognosis.

PURPOSE: Activation of MET oncogene as the result of amplification or activation mutation represents an emerging molecular target for cancer treatment. We comprehensively studied MET alterations and the clinicopathologic correlations in a large cohort of treatment-naïve non-small cell lung carcinoma (NSCLC). EXPERIMENTAL DESIGN: Six hundred eighty-seven NSCLCs were tested for MET exon 14 splicing site mutation (METΔ14), DNA copy number alterations, and protein expression by Sanger sequencing, FISH, and IHC, respectively. RESULTS: METΔ14 mutation was detected in 2.62% (18/687) of NSCLC. The mutation rates were 2.6% in adenocarcinoma, 4.8% in adenosquamous carcinoma, and 31.8% in sarcomatoid carcinoma. METΔ14 mutation was not detected in squamous cell carcinoma, large cell carcinoma, and lymphoepithelioma-like carcinoma but significantly enriched in sarcomatoid carcinoma (P < 0.001). METΔ14 occurred mutually exclusively with known driver mutations but tended to coexist with MET amplification or copy number gain (P < 0.001). Low-level MET amplification and polysomy might occur in the background of EGFR or KRAS mutation whereas high-level amplification (MET/CEP7 ratio ≥5) was mutually exclusive to the major driver genes except METΔ14. Oncogenic METΔ14 mutation and/or high-level amplification occurred in a total of 3.3% (23/687) of NSCLC and associated with higher MET protein expression. METΔ14 occurred more frequently in older patients whereas amplification was more common in ever-smokers. Both METΔ14 and high-level amplification were independent prognostic factors that predicted poorer survival by multivariable analysis. CONCLUSIONS: The high incidence of METΔ14 mutation in sarcomatoid carcinoma suggested that MET inhibition might benefit this specific subgroup of patients. Clin Cancer Res; 22(12); 3048-56. ©2016 AACRSee related commentary by Drilon, p. 2832.

Profiling of Oncogenic Driver Events in Lung Adenocarcinoma Revealed MET Mutation as Independent Prognostic Factor.

INTRODUCTION: Oncogenic driver mutations activating receptor tyrosine kinase pathways are promising predictive markers for targeted treatment. We investigated the mutation profile of an updated driver events list on receptor tyrosine kinase/RAS/PI3K axis and the clinicopathologic implications in a cohort of never-smoker predominated Chinese lung adenocarcinoma. METHODS: We tested 154 lung adenocarcinomas and adenosquamous carcinomas for EGFR, KRAS, HER2, BRAF, PIK3CA, MET, NRAS, MAP2K1, and RIT1 mutations by polymerase chain reaction-direct sequencing. MET amplification and ALK and ROS1 translocations were assessed by fluorescent in situ hybridizations. MET and thyroid transcription factor-1 protein expressions were investigated by immunohistochemistry. RESULTS: Seventy percent of lung adenocarcinomas carried actionable driver events. Alterations on EGFR (43%), KRAS (11.4%), ALK (6%), and MET (5.4%) were frequently found. ROS1 translocation and mutations involving BRAF, HER2, NRAS, and PIK3CA were also detected. No mutation was observed in RIT1 and MAP2K1. Patients with EGFR mutations had a favorable prognosis, whereas those with MET mutations had poorer overall survival. Multivariate analysis further demonstrated that MET mutation was an independent prognostic factor. Although MET protein expression was detected in 65% of lung adenocarcinoma, only 10% of the MET-immunohistochemistry positive tumors harbor MET DNA alterations that drove protein overexpression. Appropriate predictive biomarker is essential for selecting patients who might benefit from specific targeted therapy. CONCLUSION: Actionable driver events can be detected in two thirds of lung adenocarcinoma. MET DNA alterations define a subset of patients with aggressive diseases that might potentially benefit from anti-MET targeted therapy. High negative predictive values of thyroid transcription factor-1 and MET expression suggest potential roles as surrogate markers for EGFR and/or MET mutations.