Structural characterization of DNA-binding domain of essential mammalian protein TTF 1.

Transcription Termination Factor 1 (TTF1) is a multifunctional mammalian protein with vital roles in various cellular processes, including Pol I-mediated transcription initiation and termination, pre-rRNA processing, chromatin remodelling, DNA damage repair, and polar replication fork arrest. It comprises two distinct functional regions; the N-terminal regulatory region (1-445 aa), and the C-terminal catalytic region (445-859 aa). The Myb domain located at the C-terminal region is a conserved DNA binding domain spanning from 550 to 732 aa (183 residues). Despite its critical role in various cellular processes, the physical structure of TTF1 remains unsolved. Attempts to purify the functional TTF1 protein have been unsuccessful till date. Therefore, we focused on characterizing the Myb domain of this essential protein. We started with predicting a 3-D model of the Myb domain using homology modelling, and ab-initio method. We then determined its stability through MD simulation in an explicit solvent. The model predicted is highly stable, which stabilizes at 200ns. To experimentally validate the computational model, we cloned and expressed the codon optimized Myb domain into a bacterial expression vector and purified the protein to homogeneity. Further, characterization of the protein shows that, Myb domain is predominantly helical (65%) and is alone sufficient to bind the Sal Box DNA. This is the first-ever study to report a complete in silico model of the Myb domain, which is physically characterized. The above study will pave the way towards solving the atomic structure of this essential mammalian protein.

Parathyroid Hormone-Related Protein-Producing Adenocarcinoma Suspicious of Lung Cancer: A Case Report.

Introduction: Lung adenocarcinoma with parathyroid hormone (PTH)-related hypercalcemia is uncommon. Case Presentation: A 69-year-old man was admitted to our hospital due to anorexia and fatigue. Serum calcium (15.0 mg/dL) and carcinoembryonic antigen (361.7 ng/mL) were extremely high, and PTH-related protein (PTH-rP) also elevated (16.7 pmol/L). Systemic computed tomography revealed multiple enlarged lymph nodes and disseminated peritoneal nodules, with irregularly shaped nodules in the upper lobe in the left lung. Ultrasound-guided biopsy from the axillary lymph node revealed adenocarcinoma. Immunohistological staining showed the tumor cells to be positive for cytokeratin 7 and PTH-rP and negative for cytokeratin 20 and thyroid transcription factor-1. Although the primary origin remains undetermined despite detailed examinations, possible primary tumor was considered to be lung adenocarcinoma in the present case. The serum calcium level was reduced by denosumab, but the patient died 20 days after admission. Conclusion: The present case demonstrated the importance of considering oncological emergency, such as hypercalcemia and/or PTH-rP-producing hypercalcemia, in patients with adenocarcinoma.

Effect of TTF-1 expression on progression free survival of immunotherapy and chemo-/immunotherapy in patients with non-small cell lung cancer.

BACKGROUND: The choice between immunotherapy with a checkpoint inhibitor (CPI) and chemo-/immunotherapy (CIT) in patients with NSCLC stage IV is often discussed. There is some data that the effect of chemotherapy is influenced by TTF-1 expression. Little is known about the influence of thyreoid transcription factor 1 (TTF-1) expression on CIT and CPI therapy. We aimed to investigate the relationship between tumor TTF-1 expression and efficacy of CIT and CPI therapy. PATIENTS AND METHODS: We retrospectively analysed 130 patients (age 68 ± 7 y) with NSCLC stage IV. Only patients with lung adenocarcinoma were included. Patients with ALK, ROS1, RET, MET, NTRK, EGFR, BRAF mutation were excluded. Patients were treated according to the guidelines with either CPI alone (pembrolizumab, nivolumab, atezolizumab, cemiplimab) or CIT (Carboplatin/Pemetrexed/Pembrolizumab, Carboplatin/Paclitaxel/Atezolizumab). We registered patients' characteristics including TTF-1 expression. Group 1 consisted of 40 patients with CPI and TTF-1 expression, group 2 were 26 patients with CPI and with no TTF-1 expression. Group 3 consisted of 41 patients with CIT and TTF-1 expression, group 4 were 23 patients with CIT and with no TTF-1 expression. RESULTS: Group 1-4 showed comparable patients characteristics. Using cox-regression analysis, we found that TTF-1 expression resulted in an improved progression free survival (PFS) compared to patients with CPI and no TTF-1 expression (18 ± 3,15 vs. 5 ± 0,85 months, p = 0.004, 95% CI: 0,23 - 0,984). In patients, who were treated with CIT, PFS was also increased in patients with TTF-1 expression (9 ± 3,17 vs. 3 ± 0,399 months, p = 0.001, 95% CI: 0,23 - 0,85). CONCLUSIONS: In a real-life setting, we found that TTF-1 expression is associated with an increased PFS. Patients with chemo-/immunotherapy and immunotherapy seem to have a better therapy response in pulmonary adenocarcinoma with TTF-1 expression.

Subependymal Giant Cell Astrocytomas Without Tuberous Sclerosis: A Case Report on a Rare Medical Condition.

Subependymal giant cell astrocytomas (SEGAs) are benign, slow-growing, noninvasive tumors frequently associated with the tuberous sclerosis complex (TSC). The tumor's location and the patient's age should be considered carefully before diagnosis. Considering SEGA as a differential diagnosis, even in adult patients without TSC, is essential. In the present case, a 22-year-old male presented with a progressive headache, dizziness, and blurring of vision. Radiological investigations confirmed the site of the tumor, and a positive expression of thyroid transcription factor 1 in the ganglion cell component, along with the absence of germline mutation in TSC1 and TSC2, led to the final diagnosis of SEGA without TSC.

Clinical significances of TTF-1, neuroendocrine (chromogranin, synaptophysin, CD56), and keratin (pancytokeratin, CK7, CK5/6) marker immunostaining in small cell lung cancer.

PURPOSE: Immunohistochemistry (IHC) markers have established a role in the pathological diagnosis of small cell lung cancer (SCLC) and especially neuroendocrine markers help to differentiate SCLC from other tumors. The study aimed to evaluate the clinical role of different IHC markers in SCLC patients. METHODS: A total of 378 SCLC patients were enrolled in the study and analyzed retrospectively. TTF-1, neuroendocrine markers (chromogranin, synaptophysin, and CD56), and keratin markers (pancytokeratin, CK7 and CK5/6) were assessed. RESULTS: CD56 had the highest expression (92.3%) followed by pancytokeratin (82.8%), TTF-1 (74.8%), synaptophysin (72.7%), chromogranin (55.6%), CK7 (54.8%), and CK5/6 (9%). No differences were observed in the expression of all markers according to the stage of the disease. Extended disease SCLC (ED-SCLC) patients with synaptophysin expression had a higher response to chemotherapy compared to those without staining (p = 0.01); on the other hand, the chemotherapy response of these patients was not significantly different when they expressed CK7 (p = 0.06). Pancytokeratin expression was associated with favorable survival in both limited disease SCLC (LD-SCLC) (p = 0.02) and ED-SCLC (p = 0.005) patients. Similarly, ED-SCLC patients with CD56 staining lived longer than those without expression (p = 0.001). The lack of synaptophysin expression in LD-SCLC patients (p = 0.06) and TTF-1 expression in ED-SCLC patients (p = 0.06) were correlated with better survival rates. CONCLUSION: We conclude that IHC markers, used frequently in the diagnosis of SCLC, might also be used in clinical decision-making, since they are correlated with predictive and prognostic factors for the disease.

Mesonephric-type adenocarcinomas of the ovary: prevalence, diagnostic reproducibility, outcome, and value of PAX2.

Mesonephric-type (or -like) adenocarcinomas (MAs) of the ovary are an uncommon and aggressive histotype. They appear to arise through transdifferentiation from Müllerian lesions creating diagnostic challenges. Thus, we aimed to develop a histologic and immunohistochemical (IHC) approach to optimize the identification of MA over its histologic mimics, such as ovarian endometrioid carcinoma (EC). First, we screened 1,537 ovarian epithelial neoplasms with a four-marker IHC panel of GATA3, TTF1, ER, and PR followed by a morphological review of EC to identify MA in retrospective cohorts. Interobserver reproducibility for the distinction of MA versus EC was assessed in 66 cases initially without and subsequently with IHC information (four-marker panel). Expression of PAX2, CD10, and calretinin was evaluated separately, and survival analyses were performed. We identified 23 MAs from which 22 were among 385 cases initially reported as EC (5.7%) and 1 as clear cell carcinoma. The interobserver reproducibility increased from fair to substantial (κ = 0.376-0.727) with the integration of the four-marker IHC panel. PAX2 was the single most sensitive and specific marker to distinguish MA from EC and could be used as a first-line marker together with ER/PR and GATA3/TTF1. Patients with MA had significantly increased risk of earlier death from disease (hazard ratio = 3.08; 95% CI, 1.62-5.85; p < 0.0001) compared with patients with EC, when adjusted for age, stage, and p53 status. A diagnosis of MA has prognostic implications for stage I disease, and due to the subtlety of morphological features in some tumors, a low threshold for ancillary testing is recommended.

Unraveling the influence of TTF-1 expression on immunotherapy outcomes in PD-L1-high non-squamous NSCLC: a retrospective multicenter study.

Introduction: Several studies explored the association between thyroid transcription factor-1 (TTF-1) and the therapeutic efficacy of immunotherapy. However, the effect of TTF-1 on the therapeutic efficacy of programmed death-1 (PD-1) inhibitor/chemoimmunotherapy in patients with non-squamous non-small cell lung cancer (non-Sq NSCLC) with a programmed death-ligand 1 (PD-L1) tumor proportion score of 50% or more who are highly susceptible to immunotherapy remains unresolved. Therefore, we evaluated whether TTF-1 has a clinical impact on this population. Methods: Patients with non-Sq NSCLC and high PD-L1 expression who received PD-1 inhibitor monotherapy or chemoimmunotherapy between May 2017 and December 2020 were retrospectively enrolled. Treatment efficacy was compared after adjusting for baseline differences using propensity score matching. Results: Among the 446 patients with NSCLC with high PD-L1 expression, 266 patients with non-Sq NSCLC were analyzed. No significant differences in therapeutic efficacy were observed between the TTF-1-positive and -negative groups in the overall and propensity score-matched populations. Of chemoimmunotherapy, pemetrexed containing regimen significantly prolonged progression-free survival compared to chemoimmunotherapy without pemetrexed, regardless of TTF-1 expression (TTF1 positive; HR: 0.46 (95% Confidence interval: 0.26-0.81), p<0.01, TTF-1 negative; HR: 0.29 (95% Confidence interval: 0.09-0.93), p=0.02). Discussion: TTF-1 expression did not affect the efficacy of PD-1 inhibitor monotherapy or chemoimmunotherapy in patients with non-Sq NSCLC with high PD-L1 expression. In this population, pemetrexed-containing chemoimmunotherapy demonstrated superior anti-tumor efficacy, irrespective of TTF-1 expression.

Diffuse coexpression of thyroid transcription factor-1 and p40 in a non-small cell carcinoma of the lung: Second case in the female population / Coexpresión difusa del factor de transcripción tiroidea 1 y p40 en un carcinoma de célula no pequeña del pulmón: segundo caso en la población de sexo femenino

Some non-small cell carcinomas of the lung can express TTF1 and p40 in the same tumor cells. This event has been described in only six cases prior to this one, and only in one other female. It is an extraordinary event that appears as a new entity yet to be defined. The case presented is a woman with a non-small cell lung carcinoma with diffuse coexpression of TTF1 and p40 in the same cells. (AU)

Algunos carcinomas de célula no pequeña del pulmón pueden expresar TTF1 y p40 en las mismas células tumorales. Este evento se ha descrito únicamente en 6 casos anteriores a este, y solo en otra persona del sexo femenino. Se trata de un evento extraordinario que se muestra como una nueva entidad todavía por definir. El caso que se presenta versa sobre una mujer con un carcinoma de pulmón de célula no pequeña con coexpresión difusa en las mismas células de TTF1 y p40. (AU)

Gastric-Type Expression Signature in Hepatocellular Carcinoma.

It is known that V-set and immunoglobulin domain containing 1 (VSIG1) is a cell-cell adhesion molecule that can serve as an indicator of better survival in patients with gastric cancer. Its interaction with cytoplasmic thyroid transcription factor 1 (TTF-1) has been hypothesized to characterize gastric-type HCC, but its clinical importance is far from understood. As VSIG1 has also been supposed to be involved in the epithelial-mesenchymal transition (EMT) phenomenon, we checked for the first time in the literature the supposed interaction between VSIG1, TTF-1, and Vimentin (VIM) in HCCs. Immunohistochemical (IHC) stains were performed on 217 paraffin-embedded tissue samples that included tumor cells and normal hepatocytes, which served as positive internal controls. VSIG1 positivity was seen in 113 cases (52.07%). In 71 out of 217 HCCs (32.71%), simultaneous positivity for VSIG1 and TTF-1 was seen, being more specific for G1/G2 carcinomas with a trabecular architecture and a longer OS (p = 0.004). A negative association with VIM was revealed (p < 0.0001). Scirrhous-type HCC proved negative for all three examined markers. The present paper validates the hypothesis of the existence of a gastric-type HCC, which shows a glandular-like architecture and is characterized by double positivity for VSIG1 and TTF-1, vimentin negativity, and a significant OS.

Significance of NKX2-1 as a biomarker for clinical prognosis, immune infiltration, and drug therapy in lung squamous cell carcinoma.

Background: This study was performed to determine the biological processes in which NKX2-1 is involved and thus its role in the development of lung squamous cell carcinoma (LUSC) toward improving the prognosis and treatment of LUSC. Methods: Raw RNA sequencing (RNA-seq) data of LUSC from The Cancer Genome Atlas (TCGA) were used in bioinformatics analysis to characterize NKX2-1 expression levels in tumor and normal tissues. Survival analysis of Kaplan-Meier curve, the time-dependent receiver operating characteristic (ROC) curve, and a nomogram were used to analyze the prognosis value of NKX2-1 for LUSC in terms of overall survival (OS) and progression-free survival (PFS). Then, differentially expressed genes (DEGs) were identified, and Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Gene Set Enrichment Analysis (GSEA) were used to clarify the biological mechanisms potentially involved in the development of LUSC. Moreover, the correlation between the NKX2-1 expression level and tumor mutation burden (TMB), tumor microenvironment (TME), and immune cell infiltration revealed that NKX2-1 participates in the development of LUSC. Finally, we studied the effects of NKX2-1 on drug therapy. To validate the protein and gene expression levels of NKX2-1 in LUSC, we employed immunohistochemistry(IHC) datasets, The Gene Expression Omnibus (GEO) database, and qRT-PCR analysis. Results: NKX2-1 expression levels were significantly lower in LUSC than in normal lung tissue. It significantly differed in gender, stage and N classification. The survival analysis revealed that high expression of NKX2-1 had shorter OS and PFS in LUSC. The multivariate Cox regression hazard model showed the NKX2-1 expression as an independent prognostic factor. Then, the nomogram predicted LUSC prognosis. There are 51 upregulated DEGs and 49 downregulated DEGs in the NKX2-1 high-level groups. GO, KEGG and GSEA analysis revealed that DEGs were enriched in cell cycle and DNA replication.The TME results show that NKX2-1 expression was positively associated with mast cells resting, neutrophils, monocytes, T cells CD4 memory resting, and M2 macrophages but negatively associated with M1 macrophages. The TMB correlated negatively with NKX2-1 expression. The pharmacotherapy had great sensitivity in the NKX2-1 low-level group, the immunotherapy is no significant difference in the NKX2-1 low-level and high-level groups. The analysis of GEO data demonstrated concurrence with TCGA results. IHC revealed NKX2-1 protein expression in tumor tissues of both LUAD and LUSC. Meanwhile qRT-PCR analysis indicated a significantly lower NKX2-1 expression level in LUSC compared to LUAD. These qRT-PCR findings were consistent with co-expression analysis of NKX2-1. Conclusion: We conclude that NKX2-1 is a potential biomarker for prognosis and treatment LUSC. A new insights of NKX2-1 in LUSC is still needed further research.

Development of PCR-based genetic test for detection of TTF1 mutation causing abortion in Holstein Friesian cattle.

A stop-gain mutation (rs715966442; BTA11: 1,02,463,944 nucleotide position) in transcription termination factor, RNA polymerase I (TTF1) gene causes abortion in Holstein Friesian (HF) cattle. A PCR-restriction fragment length polymorphism (PCR-RFLP)-based genetic test has been developed and validated to screen the TTF1 mutation locus in HF cattle. The mutation locus was screened in 80 HF and HF crossbreds using the protocol, which revealed two animals as carriers of the mutant TTF1 allele. The test employed is cost-effective, rapid and precise and can be utilized as an effective tool for the screening of TTF1 mutation carriers in HF cattle population.

Expression patterns of HNF4α, TTF-1, and SMARCA4 in lung adenocarcinomas: impacts on clinicopathological and genetic features.

INTRODUCTION: HNF4α expression and SMARCA4 loss were thought to be features of non-terminal respiratory unit (TRU)-type lung adenocarcinomas, but their relationships remained unclear. MATERIALS AND METHODS: HNF4α-positive cases among 241 lung adenocarcinomas were stratified based on TTF-1 and SMARCA4 expressions, histological subtypes, and driver mutations. Immunohistochemical analysis was performed using xenograft tumors of lung adenocarcinoma cell lines with high HNF4A expression. RESULT: HNF4α-positive adenocarcinomas(n = 33) were divided into two groups: the variant group(15 mucinous, 2 enteric, and 1 colloid), where SMARCA4 was retained in all cases, and the conventional non-mucinous group(6 papillary, 5 solid, and 4 acinar), where SMARCA4 was lost in 3/15 cases(20%). All variant cases were negative for TTF-1 and showed wild-type EGFR and frequent KRAS mutations(10/18, 56%). The non-mucinous group was further divided into two groups: TRU-type(n = 7), which was positive for TTF-1 and showed predominantly papillary histology(6/7, 86%) and EGFR mutations(3/7, 43%), and non-TRU-type(n = 8), which was negative for TTF-1, showed frequent loss of SMARCA4(2/8, 25%) and predominantly solid histology(4/8, 50%), and never harbored EGFR mutations. Survival analysis of 230 cases based on histological grading and HNF4α expression revealed that HNF4α-positive poorly differentiated (grade 3) adenocarcinoma showed the worst prognosis. Among 39 cell lines, A549 showed the highest level of HNF4A, immunohistochemically HNF4α expression positive and SMARCA4 lost, and exhibited non-mucinous, high-grade morphology in xenograft tumors. CONCLUSION: HNF4α-positive non-mucinous adenocarcinomas included TRU-type and non-TRU-type cases; the latter tended to exhibit the high-grade phenotype with frequent loss of SMARCA4, and A549 was a representative cell line.

A case report of loss of thyroid transcription factor 1 expression in lung adenocarcinoma EBUS FNA.

We present a case report of a 76-year-old male with a histologically confirmed KRAS mutated, thyroid transcription factor 1 (TTF1) positive, grade 1, mucinous adenocarcinoma with cytologically difficult to interpret lymph node metastasis showing loss of TTF1 expression and overlapping features with goblet cell hyperplasia. The case highlights the importance of molecular testing in aiding diagnosis and guiding treatment of non-small cell lung carcinomas (NSCLC).

Diffuse coexpression of thyroid transcription factor-1 and p40 in a non-small cell carcinoma of the lung: Second case in the female population.

Some non-small cell carcinomas of the lung can express TTF1 and p40 in the same tumor cells. This event has been described in only six cases prior to this one, and only in one other female. It is an extraordinary event that appears as a new entity yet to be defined. The case presented is a woman with a non-small cell lung carcinoma with diffuse coexpression of TTF1 and p40 in the same cells.

Duodenal Papillary Metastasis of Lung Cancer with Bleeding Controlled by Endoscopic Treatment and Systemic Osimertinib Therapy: Case Report.

Introduction: Solid organ malignancies rarely metastasize to the duodenal papilla. We describe a case of primary lung cancer with duodenal papillary metastasis in a patient who presented with melena. To the best of our knowledge, this is only the second report of duodenal papillary metastasis from lung cancer. Case Presentation: A 65-year-old woman presented with complaints of anorexia, weight loss, and black stool. Imaging studies led to a clinical diagnosis of stage IVB lung cancer, and anticoagulants were initiated to treat pulmonary artery thrombosis. However, endoscopic hemostasis was challenging because of bleeding from a duodenal papillary tumor. Fortunately, the patient was positive for the plasma epidermal growth factor receptor (EGFR) gene mutation, and osimertinib, an EGFR tyrosine kinase inhibitor, was administered, successfully achieving hemostasis. Subsequently, endoscopic ultrasonography-guided transbronchial needle aspiration of an enlarged mediastinal lymph node and duodenal papillary tumor biopsy confirmed duodenal papillary metastasis of the primary lung adenocarcinoma. Conclusion: Although duodenal papillary metastasis is extremely rare, a good clinical outcome was achieved in this case by considering duodenal papillary metastasis from lung cancer as the differential diagnosis and administering systemic osimertinib therapy.

Non-small cell lung carcinoma with focal coexpression of thyroid transcription factor-1 and Δ Np63/p40: A case report.

Most lung carcinomas are subtyped by their morphologies; however, immunohistochemistry is usually performed when it is difficult to determine. The most reliable antibodies for distinguishing lung adenocarcinoma from squamous cell carcinoma are thyroid transcription factor-1 (TTF-1) and p40 (ΔNp63). In general, these markers are mutually exclusive in their expression of lung primary carcinoma; however, a few cases of non-small cell lung carcinoma (NSCLC) with coexpression of both markers have been reported. Examining a tissue microarray of 229 squamous cell carcinomas and 346 adenocarcinomas, we found one case of NSCLC with coexpression of TTF-1 and p40. Herein, we present a 71-year-old man, who had a mass lesion in the left lung apex. A transbronchial lung biopsy was performed, revealing NSCLC. He underwent left upper segmentectomy and lymph node dissection. Macroscopically, the mass showed a white-to-tan solid tumor on the cut surface. Microscopically, the tumor was composed of polygonal tumor cells which had round and vesicular nuclei with prominent nucleoli. They had an abundant amount of cytoplasm, which was slightly eosinophilic or amphophilic. Multinucleated cells with atypical nuclear features were observed to be scattered in some areas. Multifocal necrosis and hemorrhage were also noted. Distinct squamous features and obvious glandular features were absent. Immunohistochemically, the most tumor cells were coexpressed positive for both TTF-1 and p40. In our study, NSCLC with TTF-1 and p40 coexpression is rare; therefore, it is necessary to obtain further data and examine similar cases to establish more precise definitions and clinicopathological features.

Disease control in patients with non-small cell lung cancer using pemetrexed: Investigating the best treatment strategy.

BACKGROUND: Pemetrexed (PEM) is the primary chemotherapy for non-small cell lung cancer (NSCLC), showing potential for long-term disease stability in certain cases. However, studies examining disease control with PEM therapy are lacking. This study aimed to pinpoint clinical traits in patients with NSCLC responding well to PEM therapy, predict factors influencing disease control, and suggest optimal treatment approaches. METHODS: A retrospective analysis of patients with NSCLC treated with PEM was performed to compare patients who achieved disease control after treatment with those who did not. RESULTS: Of 73 patients, 56 (76.7%) achieved disease control with PEM therapy. In the disease control group, a significantly higher proportion of patients exhibited good performance status (PS) and received PEM doses without reduction after the second cycle. Multivariate analysis identified bevacizumab (Bev) noncompliance, PEM dose reduction, and thyroid transcription factor-1 (TTF-1) negativity as significant independent risk factors for disease progression during PEM therapy. Additionally, overall survival was significantly longer in the disease control group (p < 0.001). CONCLUSIONS: Our findings indicated that maintaining the dose of PEM after the second treatment cycle in patients with NSCLC, along with concurrent use of Bev and the presence of TTF-1 positivity, could enhance disease control rates and extend survival.

Clinicopathological Characteristics and Prognosis Analysis of Lung Carcinoma With p40/TTF1 Coexpression and Lung Adenosquamous Carcinoma: Lung Carcinoma With p40/TTF1 Coexpression Is a Rare Tumor With High Metastatic Potential.

Background. Lung carcinoma with p40/TTF1 coexpression (LC-PTC) is a very rare tumor with poor prognosis, and few cases have been reported to date. Objectives. To better understand biological behavior and prognosis of LC-PTC. Methods. We collected 9 examples of LC-PTC and compared them with 36 lung adenosquamous carcinomas during the same period in clinicopathologic characteristics, biologic behaviour, and prognosis. Results. Lung carcinoma with p40/TTF1 coexpression mainly occurred in middle-aged and elderly men; 8 tumors belonged to the peripheral type, and 1 belonged to the central type. The rates of lymph node and distant metastasis were 88% (7/8) and 50% (4/8), respectively; 2 patients died during follow-up. Histologically, the LC-PTC showed nest-like growth pattern without glandular growth pattern; the surface of 2 tumors was covered with ciliated columnar epithelium and tumor cells grew under the columnar epithelium. In all patients, tumor cells diffusely coexpressed p40 and TTF1. Although there was no significant difference in the maximum diameter of tumor with lymph node metastasis or with distant metastasis between LC-PTC and lung adenosquamous carcinoma, LC-PTC had a higher rate of lymph node metastasis and distant metastasis. There was no significant difference in overall survival of patients between LC-PTC and lung adenosquamous carcinoma. Additional histologic evaluation of normal pulmonary structures revealed that p40/TTF1 coexpression cells existed in bronchial mucosa and the number of cells coexpressing p40/TTF1 increased gradually from proximal bronchus to distal bronchus. Conclusions. Lung carcinoma with p40/TTF1 coexpression is a rare tumor with high metastatic potential and may originate from p40/TTF1 coexpression cells in distal bronchial mucosa.

18F-FDG PET/CT imaging in pulmonary sarcomatoid carcinoma.

Background: Pulmonary sarcomatoid carcinoma (PSC) is a rare highly aggressive and poorly differentiated non-small cell carcinoma, and little is known about the information on the usefulness of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). We investigated the clinical and 18F-FDG PET/CT features of PSC. Methods: We retrospectively analyzed 25 consecutive PSC patients who had undergone 18F-FDG PET/CT. Demographic data, PET/CT findings before treatment, pathological features, and prognosis in these patients were investigated to define correlates between maximal standard uptake value (SUVmax) and clinicopathological parameters. Results: From March 2017 to January 2023, twenty-five eligible patients with PSC were identified. There were 23 (92%) men, aged 68.5 ± 8.5 (range 56-90) years. Eighteen (72%) patients had a frequent smoking history. The mean size of PSCs was 59.3 ± 18.6 (range 29-97) mm, and 23 (92%) PSCs were Stage IV tumors. 20 (80%) lesions were located in the upper lung and 19 (76%) cases belonged to the peripheral type. Necrotic foci appeared in 21(84%) tumors. 11 (44%) PSCs invaded the pleura. All PSCs were FDG avid, and the mean of SUVmax was 11.8 ± 5.3 (range 4.8-25.5). Metastases were found on PET/CT in 24(96%) patients. The SUVmax of the lesions ≥ 5cm was higher than that of the lesions < 5cm (p=0.004), and the SUVmax of lesions with TTF-1 expression was higher than those of lesions without TTF-1 expression (p=0.009). All of the 25 primary lesions were considered malignant and confirmative, probable, and possible diagnosis of PSC was made in 2 (8%), 4 (16%), and 5(20%) patients, respectively on PET/CT. PSC was not considered in 14 (56%) patients, in PET/CT. The survival of patients with surgery didn't demonstrate a significantly good prognosis as compared with those without surgery (p=0.675). Conclusion: All PSCs had obvious FDG avidity. Although imaging diagnosis is still difficult, combined clinical and imaging features more than 40% of primary lesions were considered for the possibility of PSC in our group. Early histopathological diagnosis is necessary to help develop a reasonable regimen.