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Objective: Despite recent advances in imaging and core or endoscopic biopsies, a percentage of patients have a major lung resection without diagnosis. We aimed to assess the feasibility of a rapid tissue preparation/analysis to discriminate cancerous from non-cancerous lung tissue. Methods: Fresh sample preparations were analyzed with the Microflex LTTM MALDI-TOF analyzer. Each main reference spectra (MSP) was consecutively included in a database. After definitive pathological diagnosis, each MSP was labeled as either cancerous or non-cancerous (normal, inflammatory, infectious nodules). A strategy was constructed based on the number of concordant responses of a mass spectrometry scoring algorithm. A 3-step evaluation included an internal and blind validation of a preliminary database (n = 182 reference spectra from the 100 first patients), followed by validation on a whole cohort database (n = 300 reference spectra from 159 patients). Diagnostic performance indicators were calculated. Results: 127 cancerous and 173 non-cancerous samples (144 peripheral biopsies and 29 inflammatory or infectious lesions) were processed within 30 minutes after biopsy sampling. At the most discriminatory level, the samples were correctly classified with a sensitivity, specificity and global accuracy of 92.1%, 97.1% and 95%, respectively. Conclusions: The feasibility of rapid MALDI-TOF analysis, coupled with a very simple lung preparation procedure, appears promising and should be tested in several surgical settings where rapid on-site evaluation of abnormal tissue is required. In the operating room, it appears promising in case of tumors with an uncertain preoperative diagnosis and should be tested as a complementary approach to frozen-biopsy analysis. [ABSTRACT FROM AUTHOR]

Objectives Glucose-transporter-1 (Glut-1) may be a useful marker for differentiating B3 thymomas and thymic carcinomas. Since the literature is limited, we undertook a study to evaluate its diagnostic value in a series of thymic epithelial tumors. Materials and methods Glut-1 expression was studied by the group of pathologists linked to the French national oncological network RYTHMIC. Immunostaining was performed on a whole section of one paraffin block in a series of 92 successive surgical specimens. Patterns (focal, zonal, diffuse) and intensity of Glut-1 expression were assessed and compared with WHO histological subtypes. Results Expression was mainly restricted to epithelial cells. Immature T-lymphocytes were negative. A diffuse, moderate or strong staining was observed in most thymic carcinomas (15/16). In B3 thymomas (10/11) and in B3 thymomas borderline to thymic carcinomas (5/6), a moderate to strong zonal staining was observed at distance from vessels and fibrous septa. This pattern sometimes created the aspect of an anastomosing network in large cellular lobules. In B1 thymomas, immunostaining highlighted foci of medullary differentiation (7/8). B2 thymomas ( n = 25) were heterogeneous, with a spectrum of patterns ranging between those of B1 and B3 thymomas. Type A thymomas ( n = 5) mostly presented a weak positivity but one aggressive case showed zonal moderate/strong positivity. Most AB thymomas (15/17) showed weak to moderate immunostaining in spindle cell areas. In micronodular thymomas ( n = 3), epithelial cells and B-lymphocytes were weakly positive while follicular dendritic cells were strongly highlighted. One metaplastic thymoma displayed diffuse and moderate positivity. Conclusion Glut-1 expression globally depended on histological subtypes and the staining patterns (diffuse or zonal) were different between thymic carcinomas and type B3 thymomas. A comparative study of Glut-1 expression in atypical versus conventional type A thymomas appears warranted. Otherwise, restriction to epithelial cells makes likely a correlation with clinical assessment of glucose uptake in lymphocyte-poor tumors. [ABSTRACT FROM AUTHOR]