Ttf 1 clone 8g7g3 1

The study enrolled 171 patients with NSCLC (squamous cell carcinoma and adenocarcinoma, T_1-4N_0-3M₀) who were treated in the Cancer Research Institute, Tomsk NRMC, between 2005 and 2011. Patients were excluded if they were refused surgery and had an Eastern Cooperative Oncology Group (ECOG)/WHO performance score >2, small-cell lung cancer, associated severe diseases, and cardiovascular and pulmonary decompensation. Metastatic involvement was identified from the Local Cancer Register. The study was approved by the Institutional Review Board (IRB) (December 10, 2012; the number of approvals is 16).
The histologic diagnosis of lung cancer was made according to the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) lung adenocarcinoma classification (8 ) and the WHO criteria (9 (link)) and was confirmed by immunohistochemistry using a panel of antibodies: TTF-1 (clone 8G7G3/1, Dako), Napsin A (Rabbit Polyclonal, Cell Marque), and p63 (Rabbit Polyclonal, Leica) (Figure 1).
Cancer stage was determined according to the TNM classification (10 (link)). The type of morphological lesions in the bronchial epithelium (BCH, SM, and D) of small bronchi (d = 0.5–2 mm), obtained at a distance of ~3 cm from the tumor edge during surgery, was assessed as described earlier (11 (link)).

The tissue sections were immunostained with commercially available antibodies including thyroid transcription factor-1 (TTF-1) (clone 8G7G3/1, Dako), p40 (clone BC28, Biocare Medical) and CK5/6 (clone D5/16 B4, Dako) on a Leica BOND-MAX system (Leica Microsystems, Newcastle, UK). Tumors completely absent of TTF-1 staining were considered as TTF-1 negative. For p40 or CK5/6 staining, the moderate staining pattern was defined as 10 to 50% of tumor cells showing immunoreactivity, while the diffuse staining pattern was defined as more than 50% of tumor cells with immunoreactivity. Cases with staining intensity similar to internal controls represented by bronchial/bronchiolar basal cell layer were recognized as strong intensity.

Surgical specimens were examined and processed according to the current College of American Pathologists (CAP) guidelines. The specimens were fixed in 10% buffered formalin for 24–48 h, sampled and embedded in paraffin. Three-micrometer-thick tissue sections were cut and stained with hematoxylin and eosin (H&E). Immunohistochemical staining of sections representative of both neoplastic histotypes of primitive tumors and metastasis was carried out with the following antibodies: chromogranin A, synaptophysin, transcriptional thyroid factor-1 (TTF1, clone 8G7G3/1; Dako, Glostrup, Denmark), pan-cytokeratins (AE1-3 clone, Dako), cytokeratin 7, anaplastic lymphoma kinase (ALK, D5F3 clone, Ventana Medical Systems, Inc.), c-ROS oncogene 1 (ROS1, D4D6 clone, Cell Signaling), and tumor proportion score (TPS) of programmed death-ligand 1 (PDL1, clone 22C3, Dako) were also recorded based on recent guidelines.