Nuclear extracts from H441 adenocarcinoma cells bound to the TTF-1 binding sites, were supershifted by anti-TTF-1 antibody, and were competed by other TTF-1 DNA binding motifs.
Moreover, the regulation of TTF-1 gene expression described in this report is accompanied by the same regulation in its promoter activity, as demonstrated in transfection experiments performed in H-441 human lung-derived adenocarcinoma cells.
These tumors displayed morphological characteristics of human pulmonary adenocarcinoma such as their epithelial origin, tubulo-acinar architecture and expression of TTF-1, SP-B and proSP-C.
In this context, collagens (COL7, 17) and cytokeratins (CK6, 15, 17) are preferentially induced in squamous cell carcinoma, whereas several transcription factors (TTF1, DAT1, TF-2) are exclusively elevated in adenocarcinomas.
A recurrent gene fusion between EML4 and ALK in 6.7% of non-small cell lung cancers (NSCLCs) and NKX2-1 (TTF1, TITF1) high-level amplifications in 12% of adenocarcinomas of the lung were independently reported recently.
In this study, we investigated 14 intestinal type OMNs (borderline and adenocarcinoma) and 12 endocervical-like OMNs (borderline and adenocarcinoma) for their expression of PDX-1, CDX-2, CA-125, CK7, CK20, WT-1, D2-40, and TTF-1.
On multivariate analysis, high TTF1 expression was an independent predictor of favourable prognosis in patients with AC [hazard ratio, 0.56 (95% CI 0.38-0.83); p = 0.008].
In addition, we examined a large spectrum of lung cancer entities with neuroendocrine differentiation (ie, small cell cancers, large cell cancers, typical and atypical carcinoids) for SOX2 and TTF1 copy number gains to reveal potential molecular ties to squamous cell carcinomas or adenocarcinomas of the lung.
Napsin A-positive adenocarcinomas were significantly more prevalent among tumors characterized as relatively small (p = 0.023), non-solid predominant (p < 0.001), non-mucinous/enteric (p < 0.001), positive for TTF-1 expression (p < 0.001), and positive for EGFR mutation (p = 0.001).
In the case we report, the pulmonary-type adenocarcinoma was closely associated with a bronchial structure and exhibited diffuse positive immunohistochemical staining with TTF1, PE10, and napsin A. Molecular studies revealed no evidence of epidermal growth factor receptor mutation, a molecular alteration which may be found in primary pulmonary adenocarcinoma.
We therefore analyzed 102 large-cell carcinomas by immunohistochemistry for TTF-1 and ΔNp63/p40 as classifiers for adenocarcinoma and squamous cell carcinoma, respectively, and correlated the resulting subtypes with nine therapeutically relevant genetic alterations characteristic of adenocarcinoma (EGFR, KRAS, BRAF, MAP2K1/MEK1, NRAS, ERBB2/HER2 mutations and ALK rearrangements) or more common in squamous cell carcinoma (PIK3CA and AKT1 mutations).
Furthermore, lung adenocarcinomas with low EZH2 levels and high expression of the lineage-specific transcription factor, TTF-1, exhibited significantly improved RFS (P = 0.009; HR = 0.51) and OS (P = 0.0011; HR = 0.45), which was confirmed in the independent set of 91 adenocarcinomas.
ROS1 expression was predominantly found in female adenocarcinoma patients, in patients with low T stages, and in association with TTF1 and napsin expression, and certain histomorphological adenocarcinoma patterns (lepidic, acinar, and solid).
Out of 2,450 diagnostic samples (containing >10% of tumor cells), the occurrence of EGFR gene mutations was 9%; more frequently in women (13.9%) and adenocarcinoma patients (10%), particularly with accompanying expression of TTF1 (13.0%).
CK5/6 staining was observed in the majority of reactive specimens (78.1%) and was rare in adenocarcinoma cells (14.5%), whereas the opposite was true for IMP3 and TTF1.
The present study suggested that the combination of MUC5B and TTF-1 expression is useful for discriminating adenocarcinomas from squamous cell carcinomas, yielding prognostic significance in patients with lung adenocarcinoma.
Higher Ki67, APC, ERCC1 expressions and lower TTF1 expression were identified in advanced stages (IIA and IIIA) of adenocarcinomas, which reflect a more aggressive, less differentiated, possibly a non-TRU adenocarcinoma.
Between the AIS of smokers and nonsmokers, only the sex ratio was significantly different; all the other clinicopathologic factors including TTF-1 and driver mutations were not significantly different: EGFR and KRAS mutation rates (smokers:nonsmokers) were 61:58 (%) (P=0.7) and 6.1:1.4 (%) (P=0.2), respectively, whereas, in invasive adenocarcinomas, the rates were 41:69 (%) (P<0.001) and 9.4:2.3 (%) (P<0.04), respectively.
To improve segregation between ADC and SqCC in small samples, the classification of lung cancer was updated in 2011, adding immunohistochemistry (IHC) for p63 and TTF-1 to the diagnostic algorithm.