?(Fig.3).3). in unresectable SCC treated with tislelizumab combined with chemotherapy. Our instances added evidence of the feasibility and effectiveness of tislelizumab combined with chemotherapy in unresectable lung SCC. strong class=”kwd-title” Keywords: case statement, immune checkpoint inhibitor, lung squamous cell carcinoma, lymphocyte-to-monocyte percentage Introduction According to the 2020 Global Malignancy Statistics, the incidence and mortality rate of lung malignancy, respectively, rated second and first in all cancers, and nearly 30C40% of patients experienced locally advanced disease or distant metastases at the time of diagnosis [1,2]. The treatment of lung squamous cell carcinoma (SCC) was limited due to a lack of appropriate biomarkers and Rifamycin S novel target agents. Recent research has found that immune checkpoint inhibitor (ICI) therapy may improve lung SCC survival benefit . Tislelizumab, a mAb with high binding affinity to the programmed death 1 (PD-1) receptor, was specifically engineered to minimize Fc receptor binding on macrophages to abrogating antibody-dependent phagocytosis and potential resistance to anti-PD-1 therapy . Pharmacological analysis showed that this dissociation rate of tislelizumab was about 30-fold slower than that of nivolumab and 80-fold less than of pembrolizumab, respectively, resulting in a 35-fold to 60-fold higher target affinity of tislelizumab compared with the other two antibodies . In the beginning, for most lung cancers, tislelizumab and chemotherapy in combination exhibited encouraging antitumor activity . Subsequently, Wang em et al /em . showed that adding tislelizumab to chemotherapy significantly prolonged progress-free survival regardless of programmed death-ligand 1 (PD-L1) expression . At the same time, the adverse effects (AEs) of tislelizumab were tolerable, and most of them were grade 1 or 2 2 AEs [8,9]. However, grades 3C5 adverse events occurred in 74.1% of patients receiving pembrolizumab plus chemotherapy . This year, the National Medical Products Administration of China approved tislelizumab Rifamycin S combined with two chemotherapy regimens as the first-line drugs for advanced lung SCC. Here, we explained the cases of two Foxd1 patients with SCC who showed a good response following treatment with tislelizumab. Case reports This study was approved by the ethics committee of the Affiliated Hospital of Zunyi Medical University or college. Informed consent was obtained from the two patients. Case 1 A 69-year-old man was sent to the pneumology department due to hemoptysis for 5?months. At that time, a computed tomography (CT) revealed a 6.68?cm??6.16?cm??6.9?cm mass in the upper lobe of the left lung (Fig. ?(Fig.1),1), a 3.4?cm??2.5?cm??4.5?cm mass in the lower lobe of the right lung and multiple metastases in lung (Fig. ?(Fig.1).1). He had been smoking one packet of smokes per day for 40?years. Lung SCC was confirmed (Fig. ?(Fig.2)2) using fiberoptic bronchoscopy biopsy. Immunohistochemistry showed CK5/6 (+), P40 (+), Ki-67 (60%), TTF-1 (C), CK7(C) (Fig. ?(Fig.2).2). The membranous PD-1 and PD-L1 of tumor cells were both unfavorable by immune staining with MX003 and MXR033, respectively (Fig. ?(Fig.2).2). The cystic lesion of the liver disappeared after treatment, so we considered the lesion as distant liver metastasis. A cT4N2M1c stage IVB disease of the left lung and a cT2N2M1c stage IVB disease of the right lung were conclusive (according to the eighth edition of American Joint Committee on Malignancy). Open in a separate windows Fig. 1 CT of the primary lung lesion for case 1. (a, b, c) The primary lesion in the lung at diagnosis (arrow). (d, e, f) The second main lesion in the lung at diagnosis (arrow). (g, h, i, j, k, l) After four cycles therapy showed Rifamycin S the tumor response with CT scan (arrow). CT, computed tomography. Open in a separate window Fig. 2 Results of pathological section and immunohistochemistry. case 1: (a, b) hematoxylin-eosin staining and images were acquired (magnification 200, 400); (c, d) the result of PD-1 screening was unfavorable (magnification 200, 400); (e, f) The result of PD-L1 Rifamycin S screening was unfavorable (magnification 200, 400); (g) Rifamycin S by immunostaining, the tumor cells were diffusely positive for CK5/6 (magnification 200); (h) the diffusely positive for p40 (magnification 200); (i) by immunostaining, the tumor cells were 67% for ki-67 (magnification 200). Case 2: (k, m) hematoxylin-eosin staining and images were acquired (magnification 200, 400); (h, i) positive for PD-L1 (70%, magnification 200, 400). PD-L1, programmed death-ligand 1. Survival benefits can still be improved by ICI therapy, although PD-L1 and PD-1 were both unfavorable . We treated the patient with cisplatin 75?mg/m2, paclitaxel for injection (albumin-bound) 260?mg/m2 and tislelizumab.