False-negative PD-L1 immunostaining in ethanol-fixed EBUS-TBNA specimens of non-small cell lung cancer patients

Aims Programmed death-ligand 1 (PD-L1) immunostaining is used to predict which non-small-cell lung cancer (NSCLC) patients will respond best to treatment with programmed cell death protein 1/PD-L1 inhibitors. PD-L1 immunostaining is sometimes performed on alcohol-fixed cytological specimens instead of on formalin-fixed paraffin-embedded (FFPE) biopsies or resections. We studied whether ethanol prefixation of clots from endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) results in diminished PD-L1 immunostaining as compared with formalin fixation. Methods and results FFPE cell blocks from EBUS-TBNA specimens of 54 NSCLC patients were identified. For each case, paired samples were available, consisting of clots directly immersed in formalin and clots prefixed in Fixcyt (50% ethanol). Serial sections were immunostained for PD-L1 by use of the standardised SP263 assay and the 22C3 antibody as a laboratory-developed test (LDT). PD-L1 positivity was determined with two cut-offs (1% and 50%). Concordance of PD-L1 positivity between the formalin-fixed (gold standard) and ethanol-prefixed material was assessed. When the 22C3 LDT was used, 30% and 36% of the ethanol-prefixed specimens showed false-negative results at the 1% and 50% cut-offs, respectively (kappa 0.64 and 0.68). When SP263 was used, 22% of the ethanol-prefixed specimens showed false-negative results at the 1% cut-off (kappa 0.67). At the 50% cut-off, concordance was higher (kappa 0.91), with 12% of the ethanol-prefixed specimens showing false-negative results. Conclusion Ethanol fixation of EBUS-TBNA specimens prior to formalin fixation can result in a considerable number of false-negative PD-L1 immunostaining results when a 1% cut-off is used and immunostaining is performed with SP263 or the 22C3 LDT. The same applies to use of the 50% cut-off when immunostaining is performed with the 22C3 LDT

Socioeconomic patterns in the use of public and private health services and equity in health care

<p>Abstract</p> <p>Background</p> <p>Several studies in wealthy countries suggest that utilization of GP and hospital services, after adjusting for health care need, is equitable or pro-poor, whereas specialist care tends to favour the better off. Horizontal equity in these studies has not been evaluated appropriately, since the use of healthcare services is analysed without distinguishing between public and private services. The purpose of this study is to estimate the relation between socioeconomic position and health services use to determine whether the findings are compatible with the attainment of horizontal equity: equal use of public healthcare services for equal need.</p> <p>Methods</p> <p>Data from a sample of 18,837 Spanish subjects were analysed to calculate the percentage of use of public and private general practitioner (GP), specialist and hospital care according to three indicators of socioeconomic position: educational level, social class and income. The percentage ratio was used to estimate the magnitude of the relation between each measure of socioeconomic position and the use of each health service.</p> <p>Results</p> <p>After adjusting for age, sex and number of chronic diseases, a gradient was observed in the magnitude of the percentage ratio for public GP visits and hospitalisation: persons in the lowest socioeconomic position were 61–88% more likely to visit public GPs and 39–57% more likely to use public hospitalisation than those in the highest socioeconomic position. In general, the percentage ratio did not show significant socioeconomic differences in the use of public sector specialists. The magnitude of the percentage ratio in the use of the three private services also showed a socioeconomic gradient, but in exactly the opposite direction of the gradient observed in the public services.</p> <p>Conclusion</p> <p>These findings show inequity in GP visits and hospitalisations, favouring the lower socioeconomic groups, and equity in the use of the specialist physician. These inequities could represent an overuse of public healthcare services or could be due to the fact that persons in high socioeconomic positions choose to use private health services.</p

The effect of radio-adaptive doses on HT29 and GM637 cells

<p>Abstract</p> <p>Background</p> <p>The shape of the dose-response curve at low doses differs from the linear quadratic model. The effect of a radio-adaptive response is the centre of many studies and well known inspite that the clinical applications are still rarely considered.</p> <p>Methods</p> <p>We studied the effect of a low-dose pre-irradiation (0.03 Gy – 0.1 Gy) alone or followed by a 2.0 Gy challenging dose 4 h later on the survival of the HT29 cell line (human colorectal cancer cells) and on the GM637 cell line (human fibroblasts).</p> <p>Results</p> <p>0.03 Gy given alone did not have a significant effect on both cell lines, the other low doses alone significantly reduced the cell survival. Applied 4 h before the 2.0 Gy fraction, 0.03 Gy led to a significant induced radioresistance in GM637 cells, but not in HT29 cells, and 0.05 Gy led to a significant hyperradiosensitivity in HT29 cells, but not in GM637 cells.</p> <p>Conclusion</p> <p>A pre-irradiation with 0.03 Gy can protect normal fibroblasts, but not colorectal cancer cells, from damage induced by an irradiation of 2.0 Gy and the application of 0.05 Gy prior to the 2.0 Gy fraction can enhance the cell killing of colorectal cancer cells while not additionally damaging normal fibroblasts. If these findings prove to be true in vivo as well this may optimize the balance between local tumour control and injury to normal tissue in modern radiotherapy.</p

Immunocytochemical assessment of bone marrow aspirates for monitoring response to chemotherapy in small-cell lung cancer patients

Recent reports have suggested that tumour cell immunodetection in bone marrow of small-cell lung cancer patients is by far more frequent than found cytohistologically and may have clinical relevance. This study evaluates primarily the efficacy of chemotherapy as method of in vivo purging, but also the relationship of marrow involvement with survival. A total of 112 bone marrow aspirates from 30 chemo-naïve patients were stained twice using anti-NCAM antibodies, first at diagnosis and then after chemotherapy (24 patients) or at disease progression (six patients). Marrow contamination was associated with lower survival (P = 0.002), and was also detected in 7/17 patients conventionally staged as having limited disease. At multivariate analysis, marrow involvement was an independent factor of unfavourable prognosis (P = 0.033). The amount of tumour contamination, before and after chemotherapy, remained unchanged also in responders and even in the subset of patients with apparent limited disease. Following chemotherapy, bone marrow became tumour negative only in 25% of initially positive responders and in none of non-responders. Our results indicate that (i) chemotherapy is not effective in purging bone marrow even in chemo-responsive patients and (ii) a subset of patients with limited disease and negative bone marrow aspirates might have a more favourable prognosis. © 1999 Cancer Research Campaig