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Objectives Pulmonary sarcomatoid carcinomas (SC) are rare tumors, associated with worse prognosis and resistant to platinum-based regimens. Therapies targeting the PD-1/PD-L1 pathway are an emerging treatment for lung cancer. By characterizing intra-tumoral immune infiltration and evaluating PD-L1 expression, it could be possible to predict the efficacy of these new treatments. Materials and methods From 1997 to 2013, data from all patients with SC who underwent lung resection was collected. Tumor-immune infiltration and PD-L1 expression were studied by immunochemistry tests, analyzing CD3 (clone SP7), CD4 (clone 1F6), CD8 (clone C8/144b), CD20 (clone L26), CD163 (clone 10D6), MPO (clone 59A5), and PD-L1 (clone 5H1). Results were compared to those of 54 NSCLC. Results In total, 75 SC were included. Forty (53%) SC expressed PD-L1 vs 11 NSCLC (20%) (p < 0.0001). CD3+ tumor-infiltrating lymphocytes and CD163+ tumor-associated macrophages were more important in SC than in NSCLC (median 23% [17–30] of tumoral surface vs 17% [7–27], p = 0.011 and 23% [17–30] vs 20% [13–23], p = 0.002, respectively). In SC, the presence of Kirsten Ras (KRAS) mutations, blood vessel invasion, and TTF1+ positivity were associated with PDL1 expression. On multivariate analysis, only CD163+ macrophages and blood-vessel invasion were associated with tumoral PD-L1 expression. High levels of tumor-infiltrating lymphocytes (CD3+ or CD4+ and not CD8 + ) constituted a factor of good prognosis on survival. Interestingly, PD-L1 expression distinguishes subpopulations within tumor-infiltrating lymphocytes (CD3+ or CD4+) with different prognosis Conclusions PD-L1 expression was higher in SC than in NSCLC as well as immune-cell infiltration by TCD3 cells and macrophages. This suggests that targeting the PD-1/PD-L1 pathway could represent a new potential therapy. [ABSTRACT FROM AUTHOR]

Background: Pulmonary sarcomatoid carcinomas (SC) are tumors characterized by poor prognosis and resistance to conventional platinum-based chemotherapy. This study sought to describe the mutational profile of SC using highthroughput genotyping technology. Patients and methods: We used mass spectrometry to test 114 surgical biopsies from 81 patients with SC for 214 mutations affecting 26 oncogenes and tumor suppressor genes. Results: In total, 75 (92.6%) patients were smokers. Within the total 81 tumors, 67 distinct somatic alterations were identified, with 56 tumors (69.1%) harboring at least one mutation. The most frequent mutations were KRAS (27.2%), EGFR (22.2%), TP53 (22.2%), STK11 (7.4%), NOTCH1 (4.9%), NRAS (4.9%), and PI3KCA (4.9%). The EGFR mutations were almost always rare mutations (89%). In 32 tumors (39.5%), two or more mutations co-existed, with up to four mutations in a single case. In six different cases, comparative genetic analysis of different histological areas from the same tumor (giant, spindle, or epithelial component) revealed a 61% concordance rate for all the mutations with a 10% detection threshold, compared with 91.7% with a 20% detection threshold. Conclusion: Our results demonstrated a high mutation rate and frequent co-mutations. Despite SC tumors exhibiting a high histological heterogeneity, some intratumoral molecular homogeneity was found. Now with newly developed targeted therapies, SC patientsmay be eligible for new target mutations, and can now therefore be screened for clinical trials. [ABSTRACT FROM AUTHOR]

Summary Immunohistochemistry is often used to distinguish pulmonary sarcomatoid carcinoma from morphologic mimics. Napsin-A is a pulmonary adenocarcinoma marker, but literature on expression in sarcomatoid carcinoma is limited. Thirty-six cases of sarcomatoid carcinoma were stained for napsin, TTF-1, Oscar, CAM5.2, AE1/AE3, desmin, SMA, S-100, CK5/6, calretinin, D2-40, and WT1. Patients were 24 men and 12 women (mean, 70 years; range, 46-93). There were 27 pleomorphic carcinomas, 5 spindle cell carcinomas, 3 carcinosarcomas, and 1 giant cell carcinoma. Cases were positive for at least 1 keratin: AE1/3 was positive in all 36 cases; Oscar, in 34 cases (94%); and CAM5.2, in 32 cases (89%, weaker/more focal). Napsin was positive in 14 cases (39%): 8 diffuse, 3 focal, and 3 rare cells. TTF-1 was positive in 22 cases (61%): 15 diffuse, 3 focal, and 4 rare cells. No cases were napsin positive and negative for TTF-1. Variable staining for mesothelial markers was observed, including positivity for calretinin (12 cases, 33%), WT1 (6 cases, 17%), D2-40 (5 cases, 14%), and CK5/6 (9 cases, 25%). Mesenchymal markers were also sometimes positive (usually focal), including S-100 (4 cases, 11%), desmin (4 cases, 11%), and SMA (7 cases, 19%, 1 diffuse). In conclusion, TTF-1 is more sensitive than napsin for detection of sarcomatoid carcinoma, and no cases were positive for napsin but negative for TTF-1. CAM5.2 is less sensitive than AE1/AE3 and Oscar. Use of a thoughtful immunohistochemical panel is important in the evaluation of sarcomatoid carcinoma because mesothelial and mesenchymal markers can be expressed. [ABSTRACT FROM AUTHOR]

Abstract: Mutations of the epidermal growth factor receptor (EGFR) gene play a critical role in carcinogenesis of lung cancer, particularly adenocarcinoma. However, to the best of our knowledge, no mutations of the EGFR in patients with lung carcinosarcoma have been identified. We herein report the case of a 61-year-old female referred for a detailed examination of a left pulmonary mass shadow. Although bronchoscopy was performed, it failed to lead to a diagnosis, and video-assisted thoracoscopic surgery was therefore carried out to diagnose the tumor. The pathology revealed biphasic features consisting of both adenocarcinoma and chondrosarcoma. Intriguingly, both the adenocarcinoma and chondrosarcoma components were proven to harbor an exon19 deletion in the EGFR gene. Although carcinosarcoma is a rare malignancy of the lungs, genetic analyses of oncogenic drivers, such as the EGFR gene, should be conducted. [Copyright &y& Elsevier]