The impact of impaired tissue fixation in resected non-small-cell lung cancer on protein deterioration and DNA degradation

OBJECTIVES

The objective is to assess the impact of the quality of tissue fixation in surgical pathology on immunohistochemical (IHC) staining and DNA degradation.

MATERIALS AND METHODS

Twenty-five non-small cell lung cancer (NSCLC) resection specimens were analyzed. After resection, all tumors were processed according to the protocols in our center. In haematoxylin and eosin (H&E) stained tissue slides, adequately- and inadequately fixed tumor areas were microscopically demarcated, based on basement membrane detachment. In 10 IHC stains ALK (clone 5A4), PD-L (clone 22C3), CAM5.2, CK7, c-Met, KER-MNF116, NapsinA, p40, ROS1, TTF1) the immunoreactivity in H-scores was determined in adequately- and inadequately fixed, and necrotic tumor areas. From the same areas DNA was isolated, and DNA fragmentation in base pairs (bp) was measured.

RESULTS

H-scores were significantly higher in H&E adequately fixed tumor areas in IHC stains KER-MNF116 (H-score 256 vs 15, p=0.001) and p40 (H-score 293 vs 248, p=0.028). All other stains showed a trend towards higher immunoreactivity in H&E adequately fixed areas. Independent of H&E adequatelty- or inadequately fixed areas, all IHC stains showed significant different IHC staining intensity within tumors, suggesting heterogeneous immunoreactivity (H-scores: PD-L1 123 vs 6, p = 0.001; CAM5.2 242 vs 101, p=<0.001; CK7 242 vs 128, p=<0.001; c-MET 99 vs 20, p=<0.001; KER-MNF116 281 vs 120, p=<0.001; Napsin A 268 vs 130, p = 0.005; p40 292 vs 166, p = 0.008; TTF1 199 vs 63, p=<0.001). DNA fragments rarely exceeded a length of 300 bp, independent of adequate fixation. However, DNA fragments of 300 and 400 bp had higher concentrations in tumors with short fixation delay (<6 h vs >16 h) and short fixation time (<24 h vs >24 h).

CONCLUSIONS

Impaired tissue fixation of resected lung tumors results in decreased IHC staining intensity in some parts of the tumor. This may impact the reliability of IHC analysis.

Early Cost Effectiveness of Whole-Genome Sequencing as a Clinical Diagnostic Test for Patients with Inoperable Stage IIIB,C/IV Non-squamous Non-small-Cell Lung Cancer

BACKGROUND

Advanced non-small-cell lung cancer (NSCLC) harbours many genetic aberrations that can be targeted with systemic treatments. Whole-genome sequencing (WGS) can simultaneously detect these (and possibly new) molecular targets. However, the exact added clinical value of WGS is unknown.

OBJECTIVE

The objective of this study was to determine the early cost effectiveness of using WGS in diagnostic strategies compared with currently used molecular diagnostics for patients with inoperable stage IIIB,C/IV non-squamous NSCLC from a Dutch healthcare perspective.

METHODS

A decision tree represented the diagnostic pathway, and a cohort state transition model represented disease progression. Three diagnostic strategies were modelled: standard of care (SoC) alone, WGS as a diagnostic test, and SoC followed by WGS. Treatment effectiveness was based on a systematic review. Probabilistic cost-effectiveness analyses were performed, and threshold analyses (using €80,000 per quality-adjusted life-year [QALY]) was used to explore the early cost effectiveness of WGS.

RESULTS

WGS as a diagnostic test resulted in more QALYs (0.002) and costs (€1534 [incremental net monetary benefit -€1349]), and SoC followed by WGS resulted in fewer QALYs (-0.002) and more costs (€1059 [-€1194]) compared with SoC alone. WGS as a diagnostic test was only cost effective if it was priced at €2000 per patient and identified 2.7% more actionable patients than SoC alone. Treating these additional identified patients with new treatments costing >€4069 per month decreased the probability of cost effectiveness.

CONCLUSIONS

Our analysis suggests that providing WGS as a diagnostic test is cost effective compared with SoC followed by WGS and SoC alone if costs for WGS decrease and additional patients with actionable targets are identified. This cost-effectiveness model can be used to incorporate new findings iteratively and to support ongoing decision making regarding the use of WGS in this rapidly evolving field.

HER2 heterogeneity in adenocarcinoma of the distal esophagus and stomach

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Background: Patients with HER2 positive adenocarcinoma of the esophagus or stomach are eligible for HER2 targeted therapy, which can improve survival in selected patients. Previous research shows that HER2 gene amplification and HER2 overexpression is frequently heterogeneous within these tumors. Biopsies taken from heterogeneous tumors for predictive testing may therefore result in false-negative outcomes. The objective of this study was to assess HER2 amplification and expression in biopsies and paired resection specimens with adenocarcinoma of the esophagus or stomach, from patients who did not receive neoadjuvant systemic therapy. Methods: Paired biopsies and resection specimens of patients with adenocarcinomas of the esophagus or stomach were retrospectively selected. Immunostaining was performed on all samples using antibody 4B5 (Ventana Medical Systems) and Silver-In-Situ-Hybridization was performed in selected cases. Scoring for HER2 was performed according to the method described by Hofmann et al. (2008). Results: We included 378 cases for analysis. In both biopsies and resection specimens 14% of the cases were HER2 positive. Intratumor heterogeneity in HER2 positive tumors was present in 45% ( n= 24/53) in biopsies and 75% ( n= 39/52) in resection specimens. In HER2 positive resection specimens, 65% ( n= 34/52) of paired biopsies were also positive. In the 18 remaining discordant tumors (resection HER2 positive, biopsy negative), intratumor heterogeneity was present in 16/18 cases. For HER2 negative resection specimens all paired biopsies were also HER2 negative. SISH was performed in 110 tumors. Agreement of HER2 gene amplification between biopsy and resection specimens was observed in 86% (n = 95/110). Five HER2 negative biopsies were positive in the resection specimen. Conclusions: The results of this study indicate that predictive HER2 assessment in adenocarcinoma of the esophagus or stomach can lead to false negative results based on biopsies. As a result, patients with HER2 positive tumors can unintentionally be denied neoadjuvant HER2 targeted therapy. The set of patients investigated in this present study is unique because of the absence of any systemic and/or radiation therapy between the biopsy and the resection of the tumor. Hopefully these results can help in developing methods for improved patient selection for HER2 targeted therapy.

Multicentre study on the consistency of PD-L1 immunohistochemistry as predictive test for immunotherapy in non-small cell lung cancer

AIMS

Investigate the impact of interlaboratory- and interobserver variability of immunohistochemistry on the assessment of programmed death ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC).

METHODS

Two tissue microarrays (TMAs) were constructed from 50 (TMA-A) and 51 (TMA-B) resected NSCLC cases, and distributed among eight centres. Immunostaining for PD-L1 was performed using Agilent's 22C3 pharmDx Assay (pharmDx) and/or a 22C3 laboratory developed test (LDT). The interlaboratory variability of staining- and interobserver variability of scoring for PD-L1 were assessed in selected critical samples (samples at the cut-off of positivity) and non-critical samples. Also, PD-L1 epitope deterioration in time in stored unstained slides was analysed. Krippendorff's alpha values (0=maximal, 1=no variability) were calculated as measure for variability.

RESULTS

For interlaboratory variability of immunostaining, the percentage of PD-L1 positive cases among centres ranged 40%-51% (1% cut-off) and 23%-30% (50% cut-off). Alpha values at 1% cut-off were 0.88 (pharmDx) and 0.87 (LDT) and at 50% cut-off 0.82 (pharmDx) and 0.95 (LDT). Interobserver variability of scoring resulted in PD-L1 positive cases ranging 29%-55% (1% cut-off) and 14%-30% (50% cut-off) among pathologists. Alpha values were at 1% cut-off 0.83 (TMA-A) and 0.66 (TMA-B), and at 50% cut-off 0.77 (TMA-A) and 0.78 (TMA-B). Interlaboratory variability of staining was higher (p<0.001) in critical samples than in non-critical samples at 50% cut-off. Furthermore, PD-L1 epitope deterioration in unstained slides was observed after 12 weeks.

CONCLUSIONS

The results provide insight in factors contributing to variability of immunohistochemical assessment of PD-L1, and contribute to more reliable predictive testing for PD-L1.

Treatment strategies in recurrent esophageal or junctional cancer

Little evidence is available about survival rates in patients with recurrent disease after potentially curative surgery for esophageal or junctional cancer. Only in limited occasions, potentially curative salvage strategies are available. The aim of this study is to analyze survival rates and patterns of dissemination, and to identify independent prognostic factors in a consecutive series of patients who develop recurrent esophageal or junctional cancer. Between 1994 and 2015, patients who developed disease recurrence after neoadjuvant chemo(radio)therapy followed by radical esophagectomy for esophageal or junctional cancer were retrospectively analyzed. The Kaplan-Meier estimates were performed to calculate and compare overall survival between patients with different patterns of dissemination and to compare between different treatment strategies. Furthermore, univariate and multivariate Cox-regression analyses were performed to identify independent prognostic factors for post recurrence survival. In this study, we included 219 patients. The median overall survival of all included patients was 3.2 months (range: 0.0-101.1 months). The median overall survival in patients with exclusively locoregional recurrence (n = 23, 10.8%) was 4.9 months (range: 0.1- 55.6) and 2.9 months (range: 0.0-101.1) in patients who had distant metastases (n = 189, 89.2%), P = 0.003. Patients who received treatment aimed at complete tumor eradication (n = 28, 13.7%) had a median overall survival of 13.6 months (range: 1.1-101.1) and palliative treated patients (n = 94, 46.1%) of 4.7 months (range: 0.3-25.6), P < 0.001. In a selected group of patients survival of more than 20 months was achieved. Univariate and multivariate Cox-regression analysis showed that a higher age at the diagnosis of recurrent disease (hazard ratio: 1.087, P ≤ 0.001), an irradical resection of the primary tumor (hazard ratio: 3.355, P = < 0.001), the number of positive lymph nodes after neoadjuvant therapy (hazard ratios: ypN2 = 1.724 (P = 0.024) and ypN3 = 2.082 (P = 0.028) and the presence of a single hematogenous distant metastases (hazard ratio: 2.281, P = 0.003) or more than one hematogenous distant metastasis (hazard ratio: 2.385, P = 0.005) were associated with a shorter postrecurrence survival. The prognosis of patients who develop recurrent esophageal or junctional cancer is poor. In a selected group of patients however relatively long survival can be achieved. This offers new perspectives to improve treatment strategies and survival rates.

Wear of ultra-high molecular weight polyethylene against damaged and undamaged stainless steel and diamond-like carbon-coated counterfaces

The wear of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints and the resulting wear debris-induced osteolysis remains a major clinical concern in the orthopaedic sector. Third-body damage of metallic femoral heads is often cited as a cause of accelerated polyethylene wear, and the use of ceramic femoral heads in the hip is gaining increasing favour. In the knee prostheses and for smaller diameter femoral heads, the application of hard surface coatings, such as diamond-like carbon, is receiving considerable attention. However, to date, there has been little or no investigation of the tribology of these coatings in simulated biological environments. In this study, diamond-like carbon (DLC) has been compared to stainless steel in its undamaged form and following simulated third-body damage. The wear of UHMWPE was found to be similar when sliding against undamaged DLC and stainless steel counterfaces. DLC was found to be much more damage resistant than DLC. Under test conditions that simulate third-body damage to the femoral head, the wear of UHMWPE was seven times lower against DLC than against stainless steel (P < 0.05). The study shows DLC has considerable potential as a femoral bearing surface in artificial joints.

Reversal of diabetes by isogeneic transplantation of cultured pancreatic islets

Pancreatic islets were isolated by collagenase digestion from female Wistar rats and cultured at 20 mmol/l glucose. The enhancement of Mg++ concentration from 0.8 mmol/l up to 5.3 mmol/l had a protecting effect on the glucose-induced insulin release in the subsequent short-time incubation and prevented the age-depending decrease of B-cell function. About 1,000 cultured islets injected into portal vein normalized the plasma glucose of streptozotocin-diabetic rats. The plasma glucose patterns during the glucose load were nearly identical to healthy controls. These findings suggest that the cultured islets maintain the ability to secrete insulin in response to glucose in vitro as well as in vitro and that such islets can reverse an experimentally induced diabetes.

Effects of goldthioglucose on hormone secretion of pancreatic rat islets in vitro

Goldthioglucose enhanced independently of glucose but related to dose the insulin secretion of pancreatic rat islets in vitro. The stimulatory action is additive to that of glucose, is not inhibited by mannoheptulose and not connected with an altered glucose-utilization. The gold thioglucose-induced insulin secretion is diminished in the presence of epinephrine and Mg++, respectively, and characterized by a uniphasic response peaking at 15 min. In the absence of glucose goldthioglucose did not modify the pancreatic glucagon secretion.

Delayed or biphasic glucose-induced insulin secretion of pancreatic islets isolated from spiny mice (Acomys cahirinus) : relation to age of animals

The dynamics of insulin release from spiny mouse perifused pancreatic islets was investigated. In agreement with earlier studies we found no initial (0-10 min) insulin secretion in response to glucose in islets prepared from mice up to 35 weeks of age. The islets of animals older than 40 weeks, however, were characterized by greater insulin content, and a restored typical biphasic insulin secretion profile. The results suggest that immediate glucose response is modified by environmental or other factors related to age.

Effects of sulphydryl reagents on pancreatic glucagon secretion in vitro

The effect of sulphydryl reagents on glucagon secretion of isolated Wistar rats islets was studied. Chloromercuribenzene-p-sulphonic acid (CMBS) is a strong stimulator of glucagon secretion, whereas 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) markedly inhibited the hormone release. The effect of CMBS could not be suppressed by 20 mM glucose, but in the presence of 1 mM 4-acetamido-4'-isothiocyano-stilbene-2,2'-disulphonic acid (SITS), and is independent of the glucagon content of islets. The results let us assume that sulphydryl-groups of pancreatic A-cells are involved in the regulation of glucagon secretion.