Indirect Clinical Validation of a Programmed Death-Ligand 1 Laboratory-Developed Test for Gastric/Gastroesophageal Junction Adenocarcinoma with 22C3 Antibody Concentrate.

BACKGROUND: The PD-L1 IHC 22C3 pharmDx used on the Dako Autostainer Link 48 (ASL48) staining platform is an established method for assessing programmed death-ligand 1 (PD-L1) expression in tumor tissue and determining patient eligibility for pembrolizumab treatment; however, the availability of this platform is limited in Europe and Asia. OBJECTIVES: The aims of this study were to develop and optimize protocols for the PD-L1 22C3 antibody concentrate with multiple immunohistochemistry staining platforms and to validate these protocols using PD-L1 combined positive score (CPS) with a cut-off of ≥ 1 in gastric or gastroesophageal junction adenocarcinoma. DESIGN: The 22C3 antibody concentrate was tested and optimized protocols were developed for use with three staining platforms: Dako ASL48, Ventana BenchMark ULTRA, and Leica BOND-MAX. Tumor specimens (N = 120) from patients with gastric or gastroesophageal junction adenocarcinoma were used for the validation study; these specimens were evaluated independently by three pathologists for PD-L1 CPS as a continuous variable and using a cut-off of ≥ 1. PD-L1 IHC 22C3 pharmDx used on the Dako ASL48 platform served as the reference or gold standard. RESULTS: The intraclass correlation coefficient of CPS as a continuous variable between the gold standard and each staining platform assessed was 0.910-0.989. When CPS was dichotomized based on a cut-off of ≥ 1, depending on the pathologist and the platform used, positive percentage agreement was 81-99% and negative percentage agreement was 90-100%. Interobserver agreement using the gold standard showed substantial agreement (κ = 0.779). CONCLUSION: The PD-L1 22C3 antibody concentrate can potentially be used with the laboratory-developed test on three commercially available immunohistochemistry staining platforms to determine PD-L1 expression in tumor samples from patients with gastric or gastroesophageal junction adenocarcinoma.

Epidermal growth factor receptor (EGFR) mutations and expression in squamous cell carcinoma of the esophagus in central Asia.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) shows geographic variations in incidence, with high incidences (>50/105 person-years) in central Asia, including North Eastern Iran (Golestan) and Northern India (Kashmir). In contrast to Western countries, smoking does not appear to be a significant risk factor for ESCC in central Asia. In lung adenocarcinoma, activating mutations in the gene encoding epidermal growth factor receptor (EGFR) are frequent in tumors of never smokers of Asian origin, predicting therapeutic sensitivity to Egfr-targeting drugs. METHODS: In this study 152 cases of histologically confirmed ESCC from Iran (Tehran and Golestan Province) and North India (Kashmir Valley) have been analyzed for EGFR mutation by direct sequencing of exons 18-21. Egfr protein expression was evaluated by immunohistochemistry in 34 samples from Tehran and HER2 mutations were analyzed in 54 cases from Kashmir. RESULTS: A total of 14 (9.2%) EGFR variations were detected, including seven variations in exons. Among those, four (2.6%) were already documented in lung cancers, two were reported as polymorphisms and one was a potentially new activating mutation. All but one variation in introns were previously identified as polymorphisms. Over-expression of Egfr was detected in 22/34 (65%) of tested cases whereas no HER2 mutation was found in 54 cases from Kashmir. CONCLUSION: Overall, EGFR mutations appear to be a rare event in ESCC in high incidence areas of central Asia, although a very small proportion of cases may harbor mutations predicting sensitivity to anti-Egfr drugs.

An apoptosis methylation prognostic signature for early lung cancer in the IFCT-0002 trial.

PURPOSE: To evaluate prognostic and predictive molecular biomarkers in early-stage non-small cell lung carcinoma (NSCLC) receiving neoadjuvant chemotherapy. EXPERIMENTAL DESIGN: The IFCT-0002 trial compared two neoadjuvant regimens in 528 stages I to II NSCLC patients. DNA extraction of snap-frozen surgical samples taken from 208 patients receiving gemcitabine-cisplatin or paclitaxel-carboplatin regimens allowed for the identification of 3p allelic imbalance, Ras association domain family 1A (RASSF1A) and death-associated protein kinase 1 (DAPK1) promoter methylation, and epidermal growth factor receptor, K-ras, and TP53 mutations. Multivariate analysis identified prognostic and predictive effects of molecular alterations. A Bootstrapping approach was used to assess stability of the prognostic models generating optimism corrected indexes. RESULTS: RASSF1A methylation correlated significantly with shorter disease-free survival (DFS; adjusted HR = 1.88, 95% CI: 1.25-2.82, P = 0.0048) and shorter median overall survival (OS; adjusted HR = 2.01, 95% CI: 1.26-3.20, P = 0.020). A computed bootstrap resampling strategy led to a prognostic model, including RASSF1A, DAPK1, and tumor stage, dividing patients into three prognostic groups, with median OS ranging from 34 months for high-risk patients (HR for death = 3.85, 95% CI: 1.79-6.40) to more than 84 months for moderate (HR = 1.85, 95% CI: 0.97-3.52) and low-risk patients (reference group; P = 0.00044). In addition, RASSF1A methylation predicted longer DFS in patients treated with paclitaxel-carboplatin compared with gemcitabine-cisplatin (adjusted HR = 0.47, 95% CI: 0.23-0.97, P(interaction) = 0.042). CONCLUSIONS: Following neoadjuvant chemotherapy, RASSF1A methylation negatively impacted prognosis of early-stage NSCLC. Along with DAPK1 methylation and tumor stage, RASSF1A methylation allowed definition of three subgroups with strikingly different prognosis. Conversely, significantly longer DFS following paclitaxel-based neoadjuvant chemotherapy for patients whose tumors showed RASSF1A methylation suggested its predictive interest in stages I and II NSCLC.

Cross-validation study for epidermal growth factor receptor and KRAS mutation detection in 74 blinded non-small cell lung carcinoma samples: a total of 5550 exons sequenced by 15 molecular French laboratories (evaluation of the EGFR mutation status for the administration of EGFR-TKIs in non-small cell lung carcinoma [ERMETIC] project--part 1).

INTRODUCTION: The Evaluation of the epidermal growth factor receptor (EGFR) Mutation status for the administration of EGFR-Tyrosine Kinase Inhibitors in non-small cell lung Carcinoma (NSCLC) (ERMETIC) project part 1 assessed the accuracy of EGFR and KRAS mutations detection in NSCLC among 15 French centers. METHODS: The 15 ERMETIC centers selected 74 NSCLC surgical specimens from previously untreated patients. Paraffin and paired frozen DNA were sequenced for EGFR exons 18 to 21 and KRAS exon 2 by an external molecular laboratory, yielding a gold standard. The 74 blinded paraffin DNAs were redistributed to the 15 ERMETIC laboratories for sequencing of a total of 5550 exons. Results were compared with the gold standard and between centers by discordance rates and kappa statistics. RESULTS: The gold standard included 39 mutated samples with 22 EGFR and 17 KRAS mutated samples. Kappa statistics showed that 10, 6, and 6 of the 15 ERMETIC centers had a moderate to good kappa score, when compared with external laboratory for EGFR exon 19, EGFR exon 21, and KRAS exon 2, respectively. Kappa statistics showed moderate score between centers which increased to good for EGFR exon 19 mutation when removing 16 poor-quality samples with high nonamplificable rates. CONCLUSIONS: Paraffin-embedded specimens may represent a suitable source of DNA for sequencing analyses in ERMETIC centers. EGFR exon 19 deletions were most accurately detected by ERMETIC centers. Ease and accuracy of results, depended more on the quality of sample than on the difference in molecular sequencing procedures between centers, emphasize the need of preanalytical quality control programs.

Increased risk of gastric cancer in Japanese subjects is associated with microsatellite polymorphisms in the heme oxygenase-1 and the inducible nitric oxide synthase gene promoters.

Microsatellite polymorphism in the promoter region of the heme oxygenase-1 (HO-1) gene was analyzed jointly with that of the inducible nitric oxide synthase (iNOS) gene among Japanese subjects (control and gastric cancer patients). A higher promoter activity genotype of the HO-1 gene was associated with increased risk for gastric cancer in women. Gastric cancer risk was notably increased in subjects carrying a higher promoter activity genotype for both HO-1 and iNOS compared to those with a lower promoter activity genotype for both genes. Our data suggest that genetic polymorphisms of HO-1 and iNOS modulate individual susceptibility to gastric cancer risk.

Patterns of EGFR, HER2, TP53, and KRAS mutations of p14arf expression in non-small cell lung cancers in relation to smoking history.

Mutations in the tyrosine kinase domain of the epidermal growth factor receptor EGFR are common in non-small cell lung cancer (NSCLC) of never smokers, whereas HER2 mutations are rare. We have analyzed EGFR and HER2 mutations and the expression of the two products of the CDKN2A gene (p14(arf) and p16(INK4a)) in 116 NSCLC that have been previously analyzed for TP53 and KRAS mutations in relation to smoking history of patients. EGFR mutations were detected in 20 of 116 (17%) tumors, whereas five (4.3%) tumors contained HER2 mutations. No tumor contained both mutations. Of tumors with EGFR or HER2 mutation, 72% were adenocarcinomas, 68% were from never smokers, and 32% were from former smokers. EGFR but not HER2 mutations were mutually exclusive with KRAS mutation. Among never smokers, 11 of 16 tumors with EGFR mutation also had TP53 mutation, in contrast with two of 17 tumors without EGFR mutation (P = 0.0008). Expression of p14(arf), but not p16(ink4a), was more frequently down-regulated in never smokers (62.5%) than ever smokers (35%; P = 0.008). All tumors with EGFR or HER2 mutations and wild-type TP53 showed down-regulation of p14(arf) expression. These observations suggest that functional inactivation of the p14(arf)/p53 connection is required in tumors with EGFR or HER2 mutations, consistent with the notion that these proteins are part of a fail-safe mechanism protecting cells against untimely or excessive mitotic signals.